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Snus - Wikipedia, the free encyclopedia


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Portioned snus of the Swedish label General.
Portioned snus of the Swedish label General.

Snus (IPA: /snuːs/) is a moist powder tobacco product that is consumed by placing it under the upper lip for extended periods of time. It is a form of snuff that is used in a manner similar to American dipping tobacco, but typically does not result in the need for spitting. Snus is also unique in that it is steam-cured rather than fire-cured, is not fermented and contains no added sugar. Snus is manufactured and consumed primarily in Sweden and Norway, and is being test-marketed in several other countries.



[edit] Types

There are two main types of snus on the market:

  • originalsnus or lössnus is a loose, moist powder which can be portioned and packed into a cylindrical or spherical shape with the fingertips or snus portioner. The end result is often referred to as a pris (pinch) or prilla or prell (slang for pris).
  • portionssnus, is prepackaged powder in small bags made from the same material as teabags. It comes in smaller quantities than the loose powder but is considered easier to handle (and expectorate) than the loose powder.

Swedish snus is made from air dried tobacco from various parts of the world. In earlier times tobacco for making snus used to be laid out for drying in Scania and Mälardalen. Later Kentucky tobaccos were used. The ground tobacco is mixed with water, salt, sodium carbonate and aroma and is prepared through heating, generally via steam. Moist snus contain more than 50% water, and the average use of snus in Sweden is approximately 800 grams (16 units) per person each year. 12% (1.1 million people) of the population in Sweden uses snus[1]. Unlike American-sold oral tobacco, snus has not gone through a fermentation process.

Snus is sold mainly in Sweden and Norway,and is being trialed in South Africa and the United States. It can be found in various places frequented by Scandinavian tourists like Murmansk in Russia (with the notable exception of countries in the EU; see below). It is sold in small tins, which in the earlier years were made of porcelain, wood, silver or gold. At the time of writing, portioned snus usually comes in plastic tins of 24g, while loose snus is mostly sold in compressed paper tins with plastic lids, at 45g (50g before 2008).

Portioned snus is most commonly sold in three different variants, namely mini, normal, large and maxi. The weights may vary, but the most sold snus labels share their weight. Mini portions weigh 0.5g, with 20 pieces per tin. Standard portions weigh 1g, with 24 portions per tin, and maxi portions weigh 1.7g, with 17 pieces per tin.

The price for the 50g product is approximately €3-4 in Sweden and €7.50 in Norway as Norwegian taxes are higher.

The total production of Swedish snus, mainly for the Scandinavian market, has been reported to be in excess of 300 million units per year.[citation needed] After the Norwegian government in June 2004 implemented a strict indoor smoking ban in public places, sales of snus sky-rocketed and several new variants of the product were put on the Norwegian market.[citation needed] When the Swedish government did the same thing in June 2005, sales of snus also increased dramatically. The regulations for buying and selling snus is identical to those concerning other tobacco-based products such as cigarettes.[citation needed]

A still widely believed myth is that snus once upon a time contained small pieces of broken glass in the mixture. According to the myth, shredded fiberglass supposedly create microtears in the gums to help the tobacco ingest itself into the bloodstream, and thus becoming more addictive. But after much research from a local snuser from Norway, Bergen came out with a book where he stated that " This is a myth and not true". Kabir Ahluwalia had been to a factory and spoken with the CEO of the snus company where he agreed to the quote. [2].

[edit] Usage and storage

The most usual way to consume snus is to place it beneath the upper lip, and keep it there for a time varying from a few minutes to several hours, which varies greatly from person to person. Snus should be stored refrigerated to minimize the formation of nitrosamines. Many users report that cold snus is subjectively better than warm snus.

[edit] Health consequences

Since snus is not intended nor recommended for inhalation, it does not affect the lungs as cigarettes do, although it does contain more nicotine than cigarettes. Because it is steam-cured, rather than fire-cured like smoking tobacco or other chewing tobacco, it contains lower concentrations of nitrosamines and other carcinogens that form from the partially anaerobic heating of proteins; 2.8 parts per mil for Ettan brand compared to as high as 127.9 parts per mil in American brands, according to a study by the Commonwealth of Massachusetts Department of Health.[citation needed] The World Health Organization (WHO) acknowledges that Swedish men have the lowest rate of lung cancer in Europe, partly due to the low tobacco smoking rate, but does not argue for substituting snus for smoking, citing that the effects of snus still remain unclear.

The European Union banned the sale of snus in 1992, after a 1985 WHO study concluded that "oral use of snuffs of the types used in North America and western Europe is carcinogenic to humans", but a WHO committee on tobacco has also acknowledged that evidence is inconclusive regarding health consequences for snus consumers.[citation needed] Only Sweden and EFTA-member Norway are exempt from this ban. A popular movement during the run-up to the 1994 referendum for Sweden's EU membership made exemption from the EU criminalization of snus a condition of the membership treaty. This may be due to taxation reasons.

Recent actions by many European governments to limit the use of cigarettes has led to calls to lift the ban on snus, as it is generally considered to be less harmful than cigarette smoke, both to the user[citation needed] and to others.

[edit] Debate among public health researchers

There is some debate among public health researchers over the use of "safer" tobacco or nicotine delivery systems, generally dividing along two lines of thought. Most researchers are currently of the "abstinence" belief, believing that no form of tobacco or nicotine use is acceptable or safe, and should be minimized among the population. A minority (primarily in the European Union and Canada) believes in "harm reduction," where the belief is generally that, while it should remain a goal to reduce addiction to nicotine in the population as a whole, the reduction of harm to the health of those who choose to use nicotine should override the need to reduce overall nicotine addiction. For example, some research[3] available today shows that snus use reduces or eliminates the risk of cancers that afflict other users of tobacco products such as "chewing tobacco" (the type primarily used in the United States and Canada, created in a process similar to cigarette tobacco) and cigarettes. It is hypothesized that the widespread use of snus by Swedish men (estimated at 30% of Swedish male ex-smokers), displacing tobacco smoking and other varieties of snuff, is responsible for the incidence of tobacco-related mortality in men being significantly lower in Sweden than any other European country; in contrast, since women traditionally are less likely to use snus, their rate of tobacco-related deaths in Sweden can be compared to that of other European countries.

Snus may be less harmful than other tobacco products; according to Kenneth Warner, director of the University of Michigan Tobacco Research Network,

"The Swedish government has studied this stuff to death, and to date, there is no compelling evidence that it has any adverse health consequences. ... Whatever they eventually find out, it is dramatically less dangerous than smoking." [4]

Ongoing discussion and debates among primary scientific researchers of the effects of snus use on life expectancy appears to indicate that there is a significant increase in life expectancy among persons who previously smoked tobacco and switch to Swedish snus, depending on the age of the persons who switch, even when it is assumed that 100% of the risk of cardiovascular diseases among smokers transfers to snus users. [5] It is also noted, in the correspondence seen in the previous citation[6][7] that concerns about the effect of marketing by the tobacco industry, as influenced by the results of these scientific studies, is of primary concern to many researchers in the field, including the risk of emboldening the industry to attempt to increase snus sales among young people and promote dual-use of snus and smoked tobacco, and that the use of medical nicotine, rather than snus, can better target at-risk populations, given better access and pricing.

Opponents of snus sales maintain that, nevertheless, even the low nitrosamine levels in snus cannot be completely risk free, but snus proponents point out that inasmuch as snus is used as a substitute for smoking or a means to quit smoking, the net overall effect is positive, similar to the effect of nicotine patches, for instance.[citation needed]

In addition, rather obviously, this eliminates any exposure to second-hand smoke, further reducing possible harm to other non-tobacco users. This is seen by public health advocates who believe in "harm reduction" as a reason for recommending snus in addition to other nicotine replacement therapies rather than continued use of cancer-causing nicotine delivery systems.

This does not, however, eliminate any harm to health caused by the nicotine itself. Current research focuses on possible long-term effects on blood pressure, hypertension and possible risk of pancreatic cancer due to tobacco-specific nitrosamines (TSNAs). TSNAs are the only component of tobacco shown to induce pancreatic cancer in laboratory animals (Rivenson et al. 1988)[8]. Nicotine may also exacerbate pancreatic illness, because nicotine stimulates the gastrointestinal tract's production of cholecystokinin, which stimulates pancreatic growth and may be implicated in pancreatic cancer. Thus far the evidence specifically implicating snus in pancreatic cancer is only suggestive. [9][10]. It should also be noted that the probability of developing pancreatic cancer from cigarettes is higher than the suggested chance of developing pancreatic cancer from snus.[11][12]

[edit] Published peer-reviewed studies

[edit] Cardiovascular diseases

[edit] Diabetes

[edit] Cancer

[edit] Tobacco control

[edit] Medical community discussions and reports

[edit] General media articles

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Calmodulin - Wikipedia, the free encyclopedia

Calmodulin - Wikipedia, the free encyclopedia


From Wikipedia, the free encyclopedia

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Please help improve this article by adding reliable references. Unsourced material may be challenged and removed. (December 2007)
Calmodulin 3D structure
Calmodulin 3D structure
Flexibility of Calmodulin. Calmodulin can bind to calmodulin-dependent-protein kinase II-alpha (upper left, PDB code=1cm1); it can bind to myosine light chain (lower left, 2bbm); it can bind to edema factor toxin from the anthrax bacteria (right, 1k93) more details...
Flexibility of Calmodulin. Calmodulin can bind to calmodulin-dependent-protein kinase II-alpha (upper left, PDB code=1cm1); it can bind to myosine light chain (lower left, 2bbm); it can bind to edema factor toxin from the anthrax bacteria (right, 1k93) more details...

Calmodulin (CaM) (an abbreviation for CALcium MODULated proteIN) is a calcium-binding protein expressed in all eukaryotic cells. It can bind to and regulate a number of different protein targets, thereby affecting many different cellular functions.[1][2]



[edit] Function

CaM mediates processes such as inflammation, metabolism, apoptosis, muscle contraction, intracellular movement, short-term and long-term memory, nerve growth and the immune response. CaM is expressed in many cell types and can have different subcellular locations, including the cytoplasm, within organelles, or associated with the plasma or organelle membranes. Many of the proteins that CaM binds are unable to bind calcium themselves, and as such use CaM as a calcium sensor and signal transducer. CaM can also make use of the calcium stores in the endoplasmic reticulum, and the sarcoplasmic reticulum. CaM undergoes a conformational change upon binding to calcium, which enables it to bind to specific proteins for a specific response. CaM can bind up to four calcium ions, and can undergo post-translational modifications, such as phosphorylation, acetylation, methylation and proteolytic cleavage, each of which can potentially modulate its actions. Calmodulin can also bind to edema factor toxin from the anthrax bacteria.

[edit] Structure

Calmodulin is a small, acidic protein approximately 148 amino acids long (16706 Dalton) and, as such, is a favorite for testing protein simulation software. It contains four EF-hand "motifs", each of which binds a Ca2+ ion. The protein has two approximately symmetrical domains, separated by a flexible "hinge" region.

[edit] Mechanism

Calcium is bound via the use of the EF hand motif, which supplies an electronegative environment for ion coordination. After calcium binding, hydrophobic methyl groups from methionine residues become exposed on the protein via conformational change. This presents hydrophobic surfaces, which can in turn bind to Basic Amphiphilic Helices (BAA helices) on the target protein. These helices contain complementary hydrophobic regions. The flexibilily of Calmodulin's hinged region allows the molecule to "wrap around" its target. This property allows it to tightly bind to a wide range of different target proteins.

[edit] Family members

[edit] Other calcium-binding proteins

Calmodulin belongs to one of the two main groups of calcium-binding proteins, called EF hand proteins. The other group, called annexins, bind calcium and phospholipid (e.g., lipocortin). Many other proteins bind calcium, although binding calcium may not be considered their principal function in the cell.

[edit] See also

[edit] References

  1. ^ Stevens FC (1983). "Calmodulin: an introduction". Can. J. Biochem. Cell Biol. 61 (8): 906–10. PMID 6313166. 
  2. ^ Chin D, Means AR (2000). "Calmodulin: a prototypical calcium sensor". Trends Cell Biol. 10 (8): 322–8. doi:10.1016/S0962-8924(00)01800-6. PMID 10884684. 

[edit] External links

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Histology: muscle tissue
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Carrier protein: calcium-binding proteins