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News on Health & Science

Medical magic: Scientists try to regrow fingers

Researchers are trying to find ways to regrow fingers and someday, even limbs with tricks that sound like magic spells from a Harry Potter novel.

There is the guy who sliced off a fingertip but grew it back, after he treated the wound with an extract of pig bladder. And the scientists who grow extra arms on salamanders. And the laboratory mice with the eerie ability to heal themselves.

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This summer, scientists are planning to see whether the powdered pig extract can help injured soldiers regrow parts of their fingers. And a large federally funded project is trying to unlock the secrets of how some ani-mals regrow body parts so well, with hopes of applying the lessons to humans.

The implications for regrowing fingers go beyond the cosmetic. People who are missing all or most of their fingers, as from an explosion or a fire, often can’t pick things up, brush their teeth or button a button. If they could grow even a small stub, it could make a huge difference in their lives.

And the lessons learnt from studying regrowth of fingers and limbs could aid the larger field of regenerative medicine, perhaps someday helping people replace damaged parts of their hearts and spinal cords, and heal wounds and burns with new skin instead of scar tissue.

But that’s in the future. For now, consider the situation of Lee Spievack, a hobby-store salesman in Cincinnati, as he regarded his severed right middle finger one evening in August 2005.

He had been helping a customer with an engine on a model airplane behind the shop when the propellor sliced off the tip of his finger. The missing piece, about one centimetre long, was never found.

An emergency room doctor wrapped up the rest of his finger and sent him to a hand surgeon, who recommended a skin graft. What was gone, it appeared, was gone forever.

Spievack did have a major advantage a brother, Alan, a former Harvard surgeon who’d founded a company called ACell Inc, that makes an extract of pig bladder for promoting healing and tissue regeneration.

It helps horses regrow ligaments, for example, and the federal government has given clearance to market it for use in people. Similar formulations have been used in many people to do things like treat ulcers and other wounds and help make cartilage.

Lee Spievack took his brother’s advice to forget about a skin graft and try the pig powder. Soon a shipment of the stuff arrived and Lee Spievack started applying it every two days. Within four weeks his finger had regained its original length, he says, and in four months “it looked like my normal finger.”

Source:The Times Of India

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WHY CORNER

Why do people snore while sleeping?

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Snoring  happens  to all of us: tossing and turning sleeplessly while the person in the next room snorts and snarfs his way through the night. Why is it that a perfectly normal, healthy person makes such an awful noise?

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While breathing during sleep, structures like the palate, uvula (fleshy conical lobe at the back of the mouth) and tonsils may flap against each other as there may be excess tissue in this region. The vibration of relaxed floppy tissues that line the upper airway causes the sound that you hear when someone is snoring. This is because when you sleep, all the muscles in the body are relaxed and muscle tone decreases.

The upper airway is lined with muscles that keep the airway open. When these muscles relax during sleep, the diameter of the airway decreases and, in some people, this partially blocks the airflow, leading to turbulence.

Instead of air flowing smoothly down the airway into the lungs, it flows with gusts and bursts. Travelling through such an airway, the air picks up speed and gets whipped around in different directions. As the air bounces around, it hits the relaxed, floppy tissues lining the throat and causes them to vibrate, like a flag in the wind. This produces the snoring sound.

People don’t make a snoring sound when they are awake because the muscles in the throat hold the airway open wide enough for a smooth flow of air into the lungs.

Also, we snore more as we get older because our muscles become increasingly flaccid with age. Gaining weight also adds to the chances of snoring as fat deposits accumulate in the tissues of the airwaymaking them heavier so they fall more into the line of airflow.

Source:The Telegraph (Kolkata,India)

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Herbs & Plants

Cat’s Claw (Uncaria Tomentosa)

Botanical Name :Uncaria tomentosa

Family: Rubiaceae

Kingdom: Plantae

Division: Magnoliophyta

Class:
Magnoliopsida

Order: Gentianales

Genus: Uncaria

Species: U. tomentosa

Synonyms: Uncaria surinamensis, Nauclea aculeata, N. tomentosa, Ourouparia tomentosa
Common Names: cat’s claw, uña de gato, paraguayo, garabato, garbato casha, samento, toroñ, tambor huasca, uña huasca, uña de gavilan, hawk’s claw, saventaro

Plant parts used: bark, root, leaves

Uncaria tomentosa (popularly known in English as Cat’s Claw, in Spanish as Uña de Gato or as indian name Vilcacora) is a woody vine found in the tropical jungles of South and Central America, which derives its name from its claw-shaped thorns. It is used as an alternative medicine in the treatment of a variety of ailments.

Habitat:Cat’s claw is indigenous to the Amazon rainforest, with its habitat being restricted primarily to the tropical areas of South and Central America.
Description:Uncaria tomentosa is a liana deriving its name from hook-like thorns that resemble the claws of a cat. U. tomentosa can grow up to 30m tall, climbing by means of these thorns. The leaves are elliptic with a smooth edge, and grow in opposite whorls of two.There are two species of Cat’s Claw, Uncaria tomentosa and Uncaria guianensis, each having different properites and uses. The two are frequently confused but U. tomentosa is the more heavily researched for medicinal use   and immune modulation, while U. guianensis may be more useful for osteoarthritis. U. tomentosa is further divided into two chemotypes with different properties and active compounds, a fact ignored by most manufacturers that can have significant implications on both its use as an alternative medicine and in clinical trials to prove or disprove its efficacy.

click to see the pictures…....(01)....(1)..…….(2)..………..(3).….….…(4)………

An Astounding “New” Herb from the Peruvian Rainforests.
by Phillip Steinberg, certified nutritional consultant
For hundreds of years a rather remarkable plant has been revered and used by the indian natives of the Peruvian Amazon to “cure” cancer, arthritis, gastritis, ulcers, and female hormonal imbalances.

Researchers have determined that this plant, uncaria tomentosa, more commonly called “cat’s claw,” contains a wealth of beneficial phytochemical compounds: alkaloids, proanthocyanidins, polyphenols, triterpines, and plant sterols. Because of these compounds, cat’s claw is a powerful cellular reconstitutor, displaying significant antibacterial, antiviral, antifungal, antitumor, anti-inflammatory, and anti-oxidant properties.

According to the available research and experience of doctors working in Peru, Germany, Austria, and the United States, cat’s claw may be helpful in the treatment of: cancer; arthritis; bursitis; rheumatism; all forms of herpes; allergies; asthma; systemic candidiasis; acne; diabetes; lupus; prostatitis; chronic fatigue syndrome; PMS; irregularities of the female cycle; environmental toxin poisoning; organic depression; and those infected with the HIV virus. Evidence also suggests that cat’s claw may be effective in the treatment of numerous stomach and bowel disorders including.

The most exciting research has been the work of Dr. Klaus Keplinger, an Austrian scientist who has obtained two United States patents for isolating the alkaloids responsible for enhancing phagocytosis. This has resulted in the development of a pharmaceutical which is now being used in Austria and Germany to combat the progression of cancer and AIDS. Unfortunately, the pharmaceutical is not available in the US, but the herb is available both in tea and in capsule form.

Traditionally in Peru, a decoction is made by boiling the bark and/or root for about an hour and then drinking four or more cups of tea per day. When using capsules, three to six grams per day is considered therapeutic. However, as much as 20 grams per day might be used for several weeks at a time to treat very advanced stages of pathology.

Dr. Satya Ambrose, ND, the co-founder of the Oregon College of Oriental Medicine, has been using the bark in capsule form with some of her patients for the past several months. She said that excellent results with Crohn’s disease, ulcers, asthma, and fibromyalgia. It is observed that successes with lupus, lung cancer, prostatitis, and one patient who was able to reverse and overcome Kaposi’s sarcoma, a rare form of skin cancer associated with AIDS.

It is also found that the herb to be effective at knocking out the flu, clearing up sinus, ear, and upper respiratory infections, canker sores, lower back pain associated with arthritis, and eliminating the tired, sore muscles associated with heavy physical work and exercise. I was even able to clear up a case of athlete’s foot by putting the powdered bark between the infected toes. It can cure conjunctivitis by putting drops of the tea in eyes several times over the course of two days.

Because of research and first hand experience in using this wondrous and remarkable herb, it is believed that cat’s claw is an effective natural remedy for many of today’s serious health problems.

We can learn more about Cat’s Claw from link 1 , link2

Biochemistry
Principal active biochemicals are six oxindole alkaloids and a number of others: ajmalicine, akuammigine, campesterol, catechin, chlorogenic acid, cinchonain, corynantheine, corynoxeine, daucosterol, epicatechin, harman, hirsuteine, hirsutine, iso-pteropodine, loganic acid, lyaloside, mitraphylline, oleanolic acid, palmitoleic acid, procyanidins, pteropodine quinovic acid glycosides, rhynchophylline, rutin, sitosterols, speciophylline, stigmasterol, strictosidines, uncarine A-F, and vaccenic.

The oxindole alkaloids significantly enhance the ability of white blood cells to attack, engulf, and digest harmful microbes or foreign bodies.

Documented Properties& Actions: Analgesic, anti-inflammatory, antimutagenic, antioxidant, antiproliferative, antitumorous, antiviral, cytoprotective, cytostatic, cytotoxic, depurative, diuretic, hypotensive, immunostimulant, immunomodulatory

Medicinal uses
The parts used medicinally include the inner bark and root, taken in the form of capsules, tea and extract.

U. tomentosa is used in nootropic drugs, as well as in treatment of cancer and HIV infection. It contains several alkaloids that are responsible for its overall medical effects, as well as tannins and various phytochemicals. The chemotype of the plant determines the dominant type of alkaloid it produces, and thus its properties in vivo. One chemotype has roots which produce mostly the pentacyclic alkaloids that are responsible for the immune-strengthening effects desired by most consumers. The second chemotype produces tetracyclic oxindole alkaloids known as rhynchophylline and isorhynchophylline which counteract the immune-strengthening actions of the pentacyclic alkaloids, reduces the speed and force of the heart’s contraction, and in high doses produce ataxia, lack of coordination and sedative effects. Since U. tomentosa comes in at least these two different chemotypes, without chemical testing it is impossible to know which chemical compounds will predominate in a plant collected randomly from a natural setting.

Some ingredients appear to act as anti-inflammatory, antioxidant and anticancer agents.[6] As an herbal treatment, Cat’s Claw is used to treat intestinal ailments such as Crohn’s disease, gastric ulcers and tumors, parasites, colitis, gastritis, diverticulitis and leaky bowel syndrome, while manufacturers claim that U. tomentosa can also be used in the treatment of AIDS in combination with AZT, the treatment and prevention of arthritis and rheumatism, diabetes, PMS, chronic fatigue syndrome, prostate conditions, immune modulation, Lyme disease and systemic lupus erythematosus. A 2005 review of the scholarly literature on Cat’s Claw indicates there is supporting evidence toward its use in treating cancer, inflammation, viral infection and vascular conditions, and for its use as an immunostimulant, antioxidant, antibacterial and CNS-related agent.

In herbal medicine today, cat’s claw is employed around the world for many different conditions including immune disorders, gastritis, ulcers, cancer, arthritis, rheumatism, rheumatic disorders, neuralgias, chronic inflammation of all kinds, and such viral diseases as herpes zoster (shingles). Dr. Brent Davis, D.C., refers to cat’s claw as the “opener of the way” for its ability to cleanse the entire intestinal tract and its effectiveness in treating stomach and bowel disorders (such as Crohn’s disease, leaky bowel syndrome, ulcers, gastritis, diverticulitis, and other inflammatory conditions of the bowel, stomach, and intestines). .

Indigenous use
The indigenous peoples of South and Central America have used U. tomentosa for medicinal purposes for two thousand years or more. Researchers have investigated the use of the plant by the Asháninka tribe of Peru, who use the plant as a general health tonic, contraceptive, anti-inflammatory agent for the gastrointestinal tract, and as a treatment for diarrhea, rheumatic disorders, acne, diabetes, cancer and diseases of the urinary tract.

Allergies
Individuals allergic to plants in the Rubiaceae family and different species of Uncaria may be more likely to have allergic reactions to Cat’s Claw.Reactions can include itching, rash and allergic inflammation of the kidneys. In one documented case, kidney failure occurred in a patient with Lupus erythematosus but it is not known if this was due to an allergic reaction or another cause.

There are other plants which are known as cat’s claw (or uña de gato) in Mexico and Latin America; however, they are entirely different plants, belonging to neither the Uncaria genus, nor to the Rubiaceae family. Some of the Mexican uña de gato varieties are known to have toxic properties.

Uña de Gato,”cat’s claw”, is a thorny liana vine reputed to be a remarkably powerful immune system booster and effective in treating a wide array of maladies including cancer, systemic candidiasis, genital herpes, and AIDS (SIDA).

Uña de Gato also has anti-tumor, anti-inflammatory, and anti-oxidant properties. It has proven useful in treating arthritis, bursitis, allergies and numerous bowel and intestinal disorders. Anecdotal evidence indicates effectiveness in relieving side effects of chemotherapy.

Wild populations of this woody vine are threatened in some areas by harvesters who dig out the root out rather than simply cutting the vine and allowing regrowth. This is a foolish practice since new growth occurs rapidly when Uña de Gato vine is cut. It grows prolifically under cultivation.

Uncaria tomentosa, reputedly the most effective of several uña de gato species, is endemic to the Peruvian Amazon and is gaining international attention for its documented curative qualities.

You may click to see:->an article  from Herb Library on Cat’s Claw

Disclaimer : The information presented herein is intended for educational purposes only. Individual results may vary, and before using any supplement, it is always advisable to consult with your own health care provider.

Resources:
http://en.wikipedia.org/wiki/Uncaria_tomentosa
http://www.biopark.org/peru/unadegato.html
www.chiroweb.com

http://www.herbnet.com/Herb%20Uses_C.htm

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Herbs & Plants

Kalmegh (Andrographis paniculata Nees.)

Botanical Name: Andrographis paniculata
Family:    Acanthaceae
Genus:    Andrographis
Species:    A. paniculata
Kingdom:    Plantae
Order:    Lamiales

Common Name(s): Kalmegh (Hindi), Chuanxinlian (Chinese), Kalupnath , Kiriat , Mahatita (“ King of Bitters ), Alui , Bhunimba , Yavatikta (Sanskrit), Sambiloto (Malay)

Habitat: Kalmegh or Andrographis paniculata is a herbaceous plant in the family Acanthaceae,  native to India, China, and Southeast Asia.

It is widely cultivated in southern Asia, where it is used to treat infections and some diseases, often being used before antibiotics were created. Mostly the leaves and roots were used for medicinal purposes .

Description of the plant:

A. paniculata is an erect annual herb. The square stem has wings on the angles of new growth and is enlarged at the nodes, while the small flowers are borne on a spreading panicle. It is widely cultivated in Asia. The above-ground parts are collected in the fall. The genetic variability of the species has been examined.
It grows erect to a height of 30-110 cm in moist shady places with glabrous leaves and white flowers with rose-purple spots on the petals. Stem dark green, 0.3 – 1.0 m in height, 2 – 6 mm in diameter, quadrangular with longitudinal furrows and wings on the angles of the younger parts, slightly enlarged at the nodes; leaves glabrous, up to 8.0 cm long and 2.5 cm broad, lanceolate, pinnate; flowers small, in lax spreading axillary and terminal racemes or panicles; capsules linear-oblong, acute at both ends, 1.9 cm x 0.3 cm; seeds numerous, sub quadrate, yellowish brown.

click to see the pictures......(01)..…(1).……...(2).……...(3).……..(.4)

Cultivation
It prefers a sunny situation. The seeds are sown during May-June. The seedlings are transplanted at a distance of 60 cm x 30 cm.

Pharmacology
Andrographis paniculata plant extract is known to possess a variety of pharmacological activities. Andrographolide, the major constituent of the extract is implicated towards its pharmacological activity. A study has been conducted on the cellular processes and targets modulated by andrographolide treatment in human cancer and immune cells. Andrographolide treatment inhibited the in vitro proliferation of different tumor cell lines, representing various types of cancers. The compound exerts direct anticancer activity on cancer cells by cell cycle arrest at G0/G1 phase through induction of cell cycle inhibitory protein and decreased expression of cyclin dependent kinase 4 (CDK4). Immunostimulatory activity of andrographolide is evidenced by increased proliferation of lymphocytes and production of interleukin 2. Andrographolide also enhanced the tumor necrosis factor α production and CD marker expression, resulting in increased cytotoxic activity of lymphocytes against cancer cells, which may contribute for its indirect anticancer activity. The in vivo anticancer activity of the compound is further substantiated against B16F0 melanoma syngenic and HT 29 xenograft models. These results suggest that andrographolide is an interesting pharmacophore with anticancer and immunomodulatory activities and hence has the potential for being developed as a cancer therapeutic agent.

The herb is the well-known drug Kalmegh ‘green chiretta’, and forms the principal ingredient of a reputed household medicine (‘alui’), used as a bitter tonic and febrifuge.
Clinical Overview

Andrographis paniculata Nees (Acanthaceae), the Kalmegh of Ayurveda is an erect annual herb extremely bitter in taste in each and every part of the plant body. The plant is known in north-eastern India as  Maha-tita, literally  king of bitters  and known by various vernacular names (Table below). It is also known as   Bhui-neemâ, since the plant, though much smaller in size, shows similar appearance and has bitter taste as that of Neem (Azadirachta indica). Incidentally, the genus Andrographis consists of 28 species of small annual shrubs essentially distributed in tropical Asia. Only a few species are medicinal, of which A. paniculata is the most popular.

Properties: Analgesic* Antiparasite* Antibacterial* Astringent* Febrifuge* Stomachic* Laxative* Antispasmodic* Immunostimulant* Tonic*

Uses of Kalmegh
Kalmegh has been used for liver complaints and fevers and as an anti-inflammatory and immunostimulant. In clinical trials, Andrographis extract shortened duration and reduced symptoms of colds.

Kalmegh Dosing
Kalmegh dosage in clinical studies has ranged from 3 to 6 g of the crude plant, 1.2 g daily, or 48 mg of andrographolide daily, for common cold, tonsilitis, and familial Mediterranean fever.

Contraindications
Contraindications have not yet been identified.

Pregnancy/Lactation
Documented adverse effects. Abortifacient. Avoid use.

Kalmegh Interactions

None well documented.

Kalmegh Adverse Reactions
No data.

Toxicology

Male reproductive side effects have been studied. In rats, kalmegh decreased sperm count and motility.

History
The herb has been used primarily for liver complaints and to reduce fevers in the traditional medicine of India and China, as well as for its bitter tonic properties. A large variety of Indian herbal patent medicines are available in which A. paniculata is a prominent ingredient.

Chemistry
The diterpene lactone andrographolide was first isolated as a major constituent and later characterized as a lactone. Its full structure was determined by Cava’s group in the 1960s, while x-ray crystallography later confirmed the structure. A number of related minor diterpenes and their glycosides have since been identified. Methods of analysis including high pressure liquid chromatography (HPLC), and nuclear magnetic resonance (NMR) have been published. A method for rapid isolation of andrographolide also is available. When callus cultures of the plant were investigated, it was found that andrographolide and the other diterpenes were not produced. Instead, the sesquiterpenes paniculides A-C were found. Other constituents of the plant include various flavones.

Kalmegh Uses and Pharmacology:

It is chiefly used in viral hepatitis, diminished appetite and drug induced liver damage. It is used in loss of appetite in infants.  Andrographis paniculata has been shown to reduce liver damage due to toxins such as alcohol.  It has been demonstrated that Andrographis paniculata can protect the liver from the effects of alcohol if taken prior to consumption.  Research has also linked Andrographis paniculata to increases in immune system activity.  When supplemented with Andrographis paniculata, animals had an increase activity of both their specific and non-specific immune systems.  Andrographis paniculata may be effective in both the prevention and treatment of ailments that range from the common cold to cancer. It has also been shown to help alleviate atherosclerotic narrowing of arteries induced by high cholesterol diets.  This can, in turn, reduce the risk of heart disease and heart attacks, as well as helping the recovery of patients who already suffer from these conditions.  It is useful in burning sensation, wounds, ulcers, chronic bronchitis, leprosy, pruritis, flatulence, colic and diarrhea.

Common Uses: Colds * Diarrhea * Digestion/Indigestion * Influenza *

Liver :The aqueous extract of A. paniculata protected mice from liver damage induced by hexachlorocyclohexane, while andrographolide protected rat hepatocytes from damage by acetaminophen. Several isolated Andrographis diterpenes protected mice from liver damage by carbon tetrachloride or tert-butylhydroperoxide. Both the extract and andrographolide induced hepatic drug metabolizing enzymes in rats, although the extract was more effective than the isolated compound. An increase in bile flow was noted with administration of andrographolide to rats and guinea pigs, while it blocked the decrease in bile flow induced by acetaminophen.

Animal data:  Both antigen-specific and nonspecific immune responses in mice were stimulated by andrographolide and an ethanolic extract, although the extract was more potent than andrographolide, suggesting that other constituents also were immunostimulants. 23 Inhibition of passive cutaneous anaphylaxis and mast cell stabilization was observed in studies of the purified diterpenes in rats.

Clinical data: Research reveals no clinical data regarding the use of kalmegh to treat liver complaints.Immunostimulant and anti-infective. A small clinical study found the extract to shorten the duration of common colds and to reduce symptoms. Extracts of Andrographis have shown modest activity in vitro against HIV; however, a phase Ι study of andrographolide showed no effect on viral replication, while adverse effects required interruption of the trial after 6 weeks. Succinoylated derivatives of andrographolide have been studied for their protease inhibitory properties, which were suggested to be involved in the anti-HIV activity in vitro. Activity in antimalarial screens has also been noted for Andrographis extracts.

Other uses

The extract of A. paniculata has been shown to block E. coli enterotoxin-induced secretion in rabbit and guinea pig models of diarrhea. Andrographolide and 3 other related diterpenes were responsible for this action. An ethanol extract of Andrographis reversed elevation in blood glucose caused by streptozotocin in rats. Two purified Andrographis diterpenes stimulated nitric oxide release from cultured human endothelial cells, an effect linked to their hypotensive effect in rats. Several fractions of Andrographis were shown to reduce mean arterial blood pressure in rats, although andrographolide was not active in this model.

A water soluble extract of the plant was reported to delay death from cobra venom in mice, in line with its folk use for snakebite in India. Andrographolide has demonstrated anti-inflammatory effects in several cellular systems, including prevention of phorbol ester-induced reactive oxygen species and N -formyl-methionyl-leucyl-phenylalanine (fMLP)-induced adhesion in rat neutrophils and inhibition of TNF-induced upregulation of intercellular adhesion molecule-1 (ICAM-1) expression and monocyte adhesion. Additionally, Andrographis extract blocked rat vas deferens voltage-gated calcium channels 41 and induced cell differentiation in mouse myeloid leukemia cells, as did several diterpenes from the extract. The diversity of pharmacologic activities observed for extracts of Andrographis and its diterpenes begs the question of pharmacologic specificity, which more studies will clarify.

Dosage
Kalmegh dosage in clinical studies has ranged from 3 to 6 g of the crude plant, 1.2 g daily, or 48 mg of andrographolide daily, for common cold, tonsilitis, and familial Mediterranean fever.

Pregnancy/Lactation
Documented adverse effects. Abortifacient. Avoid use. 46

Interactions
None well documented.

Adverse Reactions
Research reveals little or no information regarding adverse reactions with the use of this product.

Toxicology
Kalmegh extracts are not acutely toxic, but the male reproductive toxicology of Andrographis has been studied. Reported infertility in rats led to a subchronic 60-day study in male rats that showed no changes in testicular weight, histology, or testosterone levels. However, detailed studies with purified andrographolide in rats over 48 days have shown decreases in sperm counts and motility, linked to disruption of spermatogenesis.

Click to learn more about:->Andrographis paniculata(Kalmegh)

> Kalmegh

Medicinal Uses of Kalmegh

Disclaimer:
The information presented herein is intended for educational purposes only. Individual results may vary, and before using any supplements, it is always advisable to consult with your own health care provider.

Resources:

:http://www.drugs.com/npp/kalmegh.html

http://www.anniesremedy.com/herb_detail354.php

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Categories
News on Health & Science

Sleep well to remember well

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Grey regions of the brain    talk to each other during deep sleep to produce great memory. T.V. Jayan on some recent findings:……....CLICK & SEE

Staying up all night studying does more harm than good  it leads to fuzzy memories the next day. In other words, our mental scrapbook’s ability to register fresh memories is seriously compromised if a good night’s sleep is denied, scientists say.

Neuroscientists have known for a while that sleep deprivation does hamper the consolidation of long-term memory    the exact mechanism of which  was unraveled recently by an India-born scientist and his colleagues in the US and Germany. But now a team of researchers from Harvard Medical School, Boston, has shown that lack of sleep not only fetters memory retention but also its very formation.

Matthew Walker and co-workers at the Harvard centre reported on February 11 in the online version of Nature Neuroscience that sleep before learning is crucial to preparing the brain for the next day’s memory formation. The findings, they say, are  worrying   considering society’s increasing erosion of sleep time.

The Harvard scientists scanned the brain’s hippocampus region   where everyday events are minted into fresh memories    using sophisticated functional Magnetic Resonance Imaging (fMRI)‘ technique. The study involved 28 volunteers in the age group of 18-30 years. The individuals were divided into two groups, with one made to stay awake for nearly 35 hours (two days and one night), and the other permitted to have a normal night’s sleep. The group that kept up was allowed to read books, take short walks, surf or chat on the Internet or play board games.

Towards the end of the second day, all participants were shown a slideshow of 150 pictures of landscapes, objects and non-celebrities. As they watched, their brains were mapped using fMRI. The scientists found that the mean recognition levels of the sleep-deprived group were about 20 per cent less than that of the other. The participants were then recalled after a full day’s break and asked to identify the slides they had earlier seen as a set of 75 fresh slides were added to the lot.  The volunteers who lacked sleep on the first day performed poorly, despite having had two nights to recover the lost sleep, the scientists said.

Your ability to learn is 20-40 per cent worse, that is, the difference between acing the exam and failing it miserably,  Walker told Know How.

While the work done by Walker and his associates conclusively proved that sleep before learning is vital, scientists had little clue about the brain mechanisms that help sleep to move and consolidate newly learnt things into long-term memory. All they knew was that for long-term storage, memories move from the hippocampus, one of the oldest regions of the brain, to the neocortex, the grey matter covering the hippocampus. This, they knew, occurred during deep, dreamless sleep.

All along, nearly for a generation, scientists thought that the hippocampus pushes the memory meant for long-term storage, or consolidation, to the neocortex. But Brown University scientist Mayank Mehta (who completed his doctoral studies from the Indian Institute of Science, Bangalore, and worked for a few years in quantum physics before moving to the US and neuroscience) and his colleagues recently proved this wrong. Their work, published in the November 2006 issue of Nature Neuroscience, showed that it is not the hippocampus that uploads information to the neocortex in a burst of brain cell communication but the neocortex that drives the dialogue.

To strike up a conversation between the hippocampus and the neocortex, the neurons from both the brain regions should be in sync. In other words, if the neocortical neurons display any activity, there should be corresponding firing among the hippocampal neurons. The previous studies failed to exhibit any such synchronous firing   which neuroscientists call phase locking  in the two regions. While neocortical neurons showed rhythmic activity during deep sleep, excitatory neurons in the hippocampus showed erratic activity.

What set Mehta thinking was that if these two parts of the brain talk during deep sleep, why didn’t they appear to be speaking the same language?

There were many reasons why scientists were unable to establish this link. One reason is that they were looking at the excitatory neurons in the hippocampus. Second, they were looking at the activity using extracellular electrodes where they can only measure the spiking activity (the rush of neurons),   Mehta told.

Mehta and his colleagues demonstrated that neurons from the neocortex work in tandem not with excitatory hippocampal neurons but what they call interneurons    inhibitory brain cells in the hippocampus. The study conducted in rats hence showed that the timing of activity or talk was the same in both the brain regions, with a small delay in the hippocampus    as if the inhibitory neurons in the hippocampus were echoing the speech in the neocortex.

What really helped Mehta to crack the mystery was his association with Nobel prize-winning German scientist Bert Sakmann. Mehta’s team used a ground breaking single-cell recording technique developed at Sakman’s laboratory at the Max Plank Institute for Medical Research in Heidelberg for recording electrical activity in rats   brains.   This technique has helped us in simultaneous measurement of electrical potential in single neurons from the hippocampus and the neocortex, Sakmann, who was in Delhi earlier this month for an Indo-EU science conference, told KnowHow.   This is by far the best technique available to accurately record electric activity of individual neurons,   Sakmann claims.

“The technique of looking inside a neuron and identifying the neural type was very important for the study. If you don’t differentiate which neuron you are recording from, it all seems like a mess,  says Mehta.

Sumantra Chattarji at the Bangalore-based National Centre for Biological Sciences admits that scientists knew the hippocampus records episodic memory whereas the neocortex plays a critical role in long-term memory storage. But they haven’t been able to get the correlation correct.   The new technique made all the difference,  says Chattarji.

This method of experimentally seeing how the two brain regions “talk” to each other may help them study other aspects of brain function such as perception and emotion, hopes Mehta.

Source:The Telegraph (Kolkata,India)

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