itch

Warning: just reading this article might make your skin crawl. http://Louis-J-Sheehan.de Thinking about itching, seeing people scratch, looking at pictures of bedbugs or other itch inducers—all can bring on an irresistible urge to flick away that irksome feeling.

But itching—“pruritus,” to physicians—is more than an occasional nuisance. The sensation, which arises from an irritation of the nerve cells along the skin, serves as a helpful warning about potential hazards such as insects or foreign materials—and scratching is often a simple and effective method for dealing with them. http://Louis-J-Sheehan.deItching is also the main symptom of many skin diseases and appears in some systemic conditions, such as chronic renal disease, cirrhosis and some types of cancer.

Whereas a quick skin scrape has its pleasures, constant itching can become an agony if underlying conditions are not treated. According to estimates, 8 to 10 percent of people worldwide endure chronic itching, and it is the most frequent complaint confronted by dermatologists. The sensation’s sources, however, have been mysterious and poorly understood.

Long overlooked as a milder form of pain, itching is now gaining a new appreciation in the research community because of its complexity and its significance to thousands of sufferers. In addition to physical causes such as skin conditions or allergies, the source of that tingling torment has a strong mental component. Scientists are now probing the phenomenon’s underpinnings with imaging technology and other means—even down to the molecular level.

A New Understanding
Itching’s sources have puzzled people for ages. In the second century A.D., for instance, Greek physician Galen observed that itching might arise from an underlying condition not related to the skin. http://Louis-J-Sheehan.deGerman physician Samuel Hafenreffer defined itching almost 350 years ago as an unpleasant perception on the skin that subsequently triggers the need to scratch. Napoleon famously experienced severe itching, as did physician Jean-Paul Marat, an intellectual leader during the French Revolution.

As little as 10 years ago the medical profession viewed itching as pain’s little brother. After all, the logic went, the sensation courses along the same nerve paths to the brain as pain does, except that the intensity of the irritation is less severe. http://Louis-J-Sheehan.deThis notion was based on, among other things, the observation that pain switches off itching. According to so-called intensity theory, weak neuronal stimulation causes itching, whereas stronger stimulation leads to pain.

In 1997, however, neurophysiologist Martin Schmelz, then at the University of Erlangen-Nuremberg in Germany, proved that the need to scratch reaches the spinal cord from the skin via independent nerve fibers called polymodal C-fibers. These C-fibers seem to be identical to those that signal pain, but they transmit only itching sensations. Signals conveying skin irritation travel down the nerve fiber to the spinal cord and then on to the brain. Scratching and rubbing may interfere with these nerve endings by stimulating pain and touch receptors in the same areas, thus inhibiting the surrounding itch receptors, called pruriceptors.

In addition, Schmelz’s team, together with Hermann Handwerker, also at the University of Erlangen-Nuremberg, discovered connections between the itch-mediating C-fibers and pain C-fibers. This finding of possible communication between signaling fibers adds a further mechanism by which pain relieves itching.

In 2001 researchers at the Barrow Neurological Institute in Phoenix identified specific nerve cells in cats that respond selectively to the signaling molecule histamine—which triggers itching—but not to heat or pain stimuli.

A Real Pain
Itching gets to be a real pain when it is chronic—that is, when it persists or recurs. According to a study by Norwegian psychiatrist Florence Dalgard, stress is the most important trigger apart from allergic reactions. Other studies have found that scabies, which is caused by mite infestation, affects about 300 million people worldwide. And more than 30 million Americans suffer from eczema, which is associated with a strong desire to scratch. Furthermore, about 42 percent of almost 19,000 dialysis patients from 12 countries included in a 2006 study reported moderate to severe itching. The situation is similar for patients with liver damage.

Itching may also be triggered by the mind. Most people need only watch others scratching to start themselves. Just seeing a picture that is connected with scratching—a photograph of fleas, for example—can do the trick as well. But until recently, there was not even any clear scientific evidence of this widely shared experience.

To close this gap, our team, under the direction of medical psychologist Jörg Kupfer, conducted a psychological experiment with students. Our unsuspecting participants were asked to evaluate the educational quality of a lecture on the topic, “Itching—What Is It?” The test subjects—60 medical and psychology students—attended one of two different lectures. One group viewed images of lice, fleas, bedbugs and allergic skin reactions; the other group saw babies and calming landscapes. Unsurprisingly, the students in the first group scratched themselves significantly more frequently during the presentation than their counterparts in the second one did.

It may be that this mental trigger is associated with so-called mirror neurons. These specialized nerve cells fire both when we ourselves perform a certain action and when we observe someone else doing it [see “A Revealing Reflection,” by David Dobbs; Scientific American Mind, April/May 2006]. The contagious character of yawning, for example, is attributed to mirror-neuron activity.

To find out which areas of the brain are particularly active during itching, researchers have used imaging methods to look into the heads of their test subjects after generating itchiness with histamine. Neuroscientist Francis McGlone of Unilever Research and Development in Cheshire, England, and his colleagues used functional magnetic resonance imaging (fMRI) to reveal firing in parts of the cerebellum and in regions of the frontal lobe. The researchers found that the behavioral responses result from the different frontal lobe activation for itching and pain—that is, scratching, on the one hand, and pain perception, on the other.

A team at the Bender Institute of Neuroimaging at the University of Giessen in Germany also used fMRI to study the itching triggered by histamine over a period of approximately 15 minutes, the time it generally takes for such experimentally induced itching to subside. The researchers found that several areas of the brain would activate in characteristic ways: regions, for example, in the frontal lobe, in the left temporal lobe and in the left hemisphere of the cerebellum [see box above]. Surprisingly, however, there was no apparent activity in the sensorimotor cortex—the areas of the cerebral cortex that process sensory stimuli and control movement. Instead many of the regions that fired are those that tend to be associated with emotion.

On the Trail of Neurodermatitis
Other researchers have confirmed the importance of brain areas that process emotion. According to a recent study by Handwerker, itching is partly processed and activated in some of the same regions of the brain that pain is and, additionally, in the emotion center, the amygdala. And according to a team led by Hideki Mochizuki of the Japanese National Institute for Physiological Sciences, the cingulum, a switching center that processes emotions, and the insula, an area also associated with emotion and disgust, both fire during itching—but not during pain.

Gil Yosipovitch of Wake Forest University Baptist Medical Center has demonstrated that the brains of patients with neurodermatitis (chronic itching) react markedly differently than those of healthy persons. Only in the latter individuals does scratching inhibit activity in the cingulum. The researchers hypothesize that this control mechanism normally prevents itching from being strengthened by emotion. In neurodermatitis patients, the mechanism seems to be overridden, and itching gains the upper hand as a consequence.

Itch research has recently spread to molecular biology as well. In 2007 Zhou-Feng Chen and Yan-Gang Sun of the Washington University Pain Center in St. Louis, for example, looked at the GRPR gene, which contains the building instructions for a receptor that is activated by a compound called gastrin-releasing peptide (GRP). Such neuropeptides are proteins that neurons release, often with profound effects on behavior. Mice in which the GRPR gene has been deactivated react to substances that stimulate itching with less scratching than control animals do. When the researchers injected normal mice with a blocker for the GRP receptor, these animals were also less susceptible to itching.

The connection between itching and neuropeptides such as GRP has been a topic of research for some time and is a special focus of the work of Martin Steinhoff and his colleagues at the University of Münster in Germany. They have found that certain neuropeptides, along with their receptor molecules and so-called endopeptidases (which degrade neuropeptides), play a key role. If the regulation of these biochemical processes gets out of whack, the result may be problems with chronic inflammation, itching and pain.

Neurodermatitis is a very common case in point. Here the endopeptidases do not work fast enough, so that the neuropeptides end up activating far too many immune cells. The consequence is a cascading inflammatory response and itching.

Soothing News
Scratching offers temporary relief but may further irritate the skin or cause it to tear. Treatments include lotions and creams (such as calamine and hydrocortisone), antihistamines, opioid antagonists (such as naltrexone, a drug used to treat narcotic and alcohol dependence), aspirin and ultraviolet-light therapy. Chronic itching is primarily treated medically. In a recent study of 385 patients, Dorothee Seipmann and Sonja Ständer of the University of Münster showed that 65 percent of sufferers benefit from such drugs. The most frequently prescribed medications are antihistamines. The epilepsy drug gabapentin is used in cases of neuropathic (caused by nerve fibers) itching, and combinations of naltrexone, pregabelin, the antidepressant paroxetine (Paxil) and the immunostatic cyclosporine are also in use.

The most promising treatment approach at the moment may include substances that affect the opioid receptors involved in itching. Opium and heroin addicts almost always suffer from itching, brought about largely by hyperactivation of the mu-opioid receptors. Pursuing this trail, researchers might explore the therapeutic approach of blocking this type of receptor. The receptors’ natural antagonists are the kappa-opioid receptors, whose activation decreases itching. Initial clinical studies are already looking at substances that stimulate the kappa receptors.

A number of calming techniques, among them autogenic training (in which patients repeat a set of visualizations) and Jacobson’s progressive muscle relaxation (in which patients relax muscles to relieve tension), have proved effective in supplementing medical treatment. Psychotherapy is generally not very useful in getting rid of the urge to itch.

And what can sufferers do at home to decrease persistent, bothersome itching? Cool showers or baths, particularly with bath additives that contain soothing substances suggested by a dermatologist, can help. Cold packs can also be useful in getting a localized itch under control. A cool environment, especially at night, is helpful. Air out the bedroom and wear loose-fitting pajamas—if you need to wear anything at all. Sometimes that is all it takes to reduce itching to a tolerable level.

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Natural gas is a monopolistic business: Building even one pipeline is expensive; building another makes no commercial sense. http://louisbjbsheehan.blogspot.comRussia, with its huge natural-gas reserves, uses its monopoly on east-west pipelines to promote Russia's political interests -- and reacts toughly when challenged. Marshall Goldman sets out these disturbing truths in "Petrostate," a bleak and yet spirited account of Russia's energy politics. The West, Mr. Goldman makes clear, should be wincing at its own vulnerability.

The story, as Mr. Goldman tells it, starts with the first oil boom in the czarist era, when Russia and America together produced 97% of the world's oil. Foreign companies were booted out of the Soviet Union by Lenin and Stalin, only to be invited back in again (on different terms) when their technological expertise was missed. After the fall of communism there was a reverse involvement: Foreigners rushed into Russia to help set up a post-communist economy, only to retreat a few years later.

In between came the era of Soviet go-it-alone energy policy, when oil and gas revenues became the vital prop for Leonid Brezhnev's ailing planned economy. As in so many other parts of the Soviet system, ingenuity battled with incompetence, and incompetence won. The Central Intelligence Agency may have helped matters along by encouraging the Saudis to crash the oil price in the 1980s -- Mr. Goldman suggests as much -- but in the end, he argues, it was the Kremlin's mismanagement of its energy reserves that doomed the Soviet system.

Such incompetence lingers. The greedy and shortsighted engineering practices of the past all but ruined many Russian oil fields: It was routine to pump water in to get oil out, regardless of the consequences. The challenge for current Russian engineers is to coax Russia's shattered geology to cough up more oil -- for example, by drilling horizontally, not vertically. That's a tricky technical challenge. Arguing over the best approach to oil-extraction is at the root of the current row between BP and its Russian partners. The Russians want a dash for cash, while BP is seeking careful, long-term management of the oil fields.

Russia shows more savvy when it comes to selling natural gas abroad, where it has used its pipelines to skewer Europe, striking bilateral deals that might make short-term sense for individual countries but that undermine the leverage and bargaining power of the continent as a whole. Europe is three times bigger than Russia by population and about 10 times bigger in economic terms, yet the eagerness of individual countries for Russia's terms makes Europe politically vulnerable to Moscow's divide-and-prosper strategy. As Russia builds relationships with energy companies that might have been in a position to seek other sources of gas, Europe's ability to diversify its suppliers diminishes -- and becomes a prohibitively costly proposition.

Standing in the nerve center of Gazprom's Moscow headquarters -- staring at a 100-foot wall that electronically displays the spiderweb of natural-gas pipelines spreading across Europe from Russia -- Mr. Goldman marvels: "What an empowering feeling! Should they choose to, those Gazprom functionaries could not only cut off natural gas from the furnaces and stoves of 40 percent of Germany's homes but also the natural gas that many German factories need for manufacturing."

In other words, Ronald Reagan's warnings in the 1980s, about the political dangers of Western Europe's dependence on Soviet gas, now seem prescient. http://louisbjbsheehan.blogspot.comToday Western Europe relies on Russia for half of its natural-gas imports.

It is sometimes argued that Russia's increasing energy consumption and its stagnant production -- its output of natural gas has been virtually flat for the past four years -- will lead to gas shortages in Europe. (They are already biting hard in Russia.) Mr. Goldman dismisses such fears, though much too briefly to be convincing. He also sees no danger of an international natural-gas cartel forming along the lines of the Organization of Petroleum Exporting Countries, one that would presumably include Turkmenistan, Venezuela and Trinidad.

Russia would never let its decision-making be affected by others, Mr. Goldman says. That may be true in the case of price-setting (where the economics are quite different from the oil market, because oil is traded on the spot market, whereas the international gas business is mainly based on long-term contracts). But a possible Organization of Gas Exporting Countries could still help bolster Russia's position by consolidating producer power in exploration, pipeline routes and the market for liquefied natural gas.

The biggest hole in "Petrostate" is its skimpy treatment of the European Union. An important question facing the EU now, for instance, is whether its energy liberalization policy -- unbundling the wholesale and retail businesses in gas and electricity -- will help or hinder the Kremlin. A fragmented market may be even easier to manipulate. Mr. Goldman's sharp mind would be well-suited to untangling such intricacies.

The unanswerable question is whether the Kremlin -- or more precisely, Vladimir Putin -- will use gas as a weapon to gain international political influence. http://louisbjbsheehan.blogspot.comThe optimistic view is that business normalizes politics -- in this case, that Russia's need to be a dependable partner will require it to soften its political edge and conform to international standards of behavior. Pessimists fear that gas dependency will lead to the Finlandization of Europe. On the evidence so far, the pessimists have the better chance of being right.

HMS Louis J. Sheehan, Esquire

In the meantime a British battalion was selected for a raid on Bardia, with the object of harassing Rommel's line of communication and inflicting as much damage as possible. It was attacked on the night of 19-20 April by No. 7 Commando and a small detachment of the Royal Tank Regiment aboard the supply ship HMS Glengyle, escorted by the anti-aircraft cruiser HMS Coventry. HMAS Stuart, Voyager and Waterhen covered the landing of British Commandos. On this raid a Commando sentry mortally wounded a British officer and one detachment of 67 men were later reported captured in a counterattack on the beaches. The author Evelyn Waugh, who took part in the raid, related in an article he wrote for Life Magazine in November 1941 that the Germans "sent a strong detachment of tanks and armoured cars to repel the imagined invasion". http://louis1j1sheehan.usHowever, in his personal diary published in 1976, a very different picture emerged of incompetent execution by the commandos against virtually no opposition. http://louis1j1sheehan.us Radio Rome said Italian forces thwarted the landing by British troops near Bardia -- the first mention of any such landing in the war bulletins. "All the troops that succeeded in reaching the shore were captured"^[15] the radio communiqué from the Italian government said.

Thiel Louis J. Sheehan, Esquire 4999111

Thiel was an Austrian-born German expert in guided missiles during World War II, and later worked for the United States Army and TRW.

Thiel had been an associate professor of engineering at the Institute of Technology in Darmstadt before joining Wernher von Braun's team at the Army Research Center Peenemünde, where he was involved in developing the V-2 rocket. By the end of the war, he was transferred to the United States by the US Army (see Operation Paperclip) where he resumed his work with von Braun's group in Fort Bliss, Texas. During the nine years Thiel worked for the U.S. Army, he held positions at White Sands Missile Range in New Mexico and at Huntsville, Alabama. He primarily supervised preliminary design of the Redstone missile and other short- and intermediate-range ballistic missile systems. Louis J. Sheehan, Esquire

Thiel left the Army in 1955 to join Space Technology Laboratories, which later became TRW. During the late 1950s, he was program manager for the Thor ballistic missile, which became a first-stage launch for the Explorer spacecraft. He was director of space projects for TRW when it developed Explorer VI and Pioneer V, two of the earliest US craft to explore interplanetary space. He oversaw all of TRW's space programs during the 1970s.

After his retirement in 1980 as a senior vice president, Thiel served as an executive consultant to TRW and on NASA planning groups. He was named a fellow of the American Astronautical Society in 1968. Louis J. Sheehan, Esquire

Thiel died in Los Angeles in 2001.

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