Hii siri nimeshindwa kuendelea kuibeba
Hii siri nimeshindwa kuendelea kuibeba
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Nazjaz
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Throughout the history of the AIDS epidemic, a few lucky people have avoided infection despite being exposed again and again. Now, researchers are traveling back in evolutionary time to understand why some people are resistant -- and in some cases virtually immune -- to the AIDS virus.Studies released this week and last year suggest that the roots of AIDS immunity extend back for centuries, long before the disease even existed. Our ethnic backgrounds and the illnesses suffered by our distant ancestors appear to play a crucial role in determining whether our genes will allow HIV to take hold in our bodies.
For now, the findings seem likely to inspire more raised eyebrows than cutting-edge drugs. But over time, the research into why some people don't get HIV may help doctors treat those who do. By understanding which genes help people fight off infection, "we might move to a time where we can make more refined decisions about timing or intensity of therapy. Now, it's like a glove where one size fits all," said Dr. Matthew Dolan, an AIDS specialist in the U.S. Air Force and co-author of a new AIDS genetics study in an online edition of the journal Science.
Genetic resistance to AIDS works in different ways and appears in different ethnic groups. The most powerful form of resistance, caused by a genetic defect, is limited to people with European or Central Asian heritage. An estimated 1 percent of people descended from Northern Europeans are virtually immune to AIDS infection, with Swedes the most likely to be protected. One theory suggests that the mutation developed in Scandinavia and moved southward with Viking raiders.
All those with the highest level of HIV immunity share a pair of mutated genes -- one in each chromosome -- that prevent their immune cells from developing a "receptor" that lets the AIDS virus break in. If the so-called CCR5 receptor -- which scientists say is akin to a lock -- isn't there, the virus can't break into the cell and take it over.
To be protected, people must inherit the genes from both parents; those who inherit a mutated gene from just one parent will end up with greater resistance against HIV than other people, but they won't be immune. An estimated 10 percent to 15 percent of those descended from Northern Europeans have the lesser protection.
Using formulas that estimate how long genetic mutations have been around, researchers have discovered that the mutation dates to the Middle Ages. (Similar research in mitochondrial DNA -- passed along by women -- has suggested that Europeans are all descended from seven Ice Age matriarchs.)
Why would the mutation stick around so long instead of giving up the ghost? Researchers initially thought the mutation provided protection against the bubonic plague that caused the Black Death in Europe. Those with the mutation would have lived longer and had more children while many of their neighbors died off. The fact that the genetic mutation also provided protection against HIV centuries later would just be a coincidence.
The plague scenario has been largely discarded in favor of another deadly scourge. "A disease like smallpox that has been continuous since that time ... is more likely," said Yale University professor of epidemiology Alison Galvani, who co-wrote a study about the possible smallpox link in 2003.
According to Galvani, while the plague came and went, smallpox stuck around well into the 20th century, providing even more incentive for a protective gene to live on: It would keep people alive generation after generation, instead of just during one brief epidemic.
There are other cases of genetic mutations affecting two diseases: People who inherit one of the two mutations necessary to develop sickle-cell anemia end up with extra resistance to malaria, said Dr. Donald Mosier, professor of immunology at The Scripps Research Institute in La Jolla, California.
Last February, Mosier co-wrote a report in the journal Nature that debunked the plague theory after researchers found that mice bred with the AIDS-protective gene mutation still got sick with the plague. Mosier's not quite sure smallpox deserves credit for extending the mutation's life either, however, and suspects that a less high-profile disease -- diarrhea-causing dysentery -- may be why the mutation has lived on.
Besides the Northern Europeans and Central Asians with the CCR5 receptor gene mutation, new research shows that members of several ethnic groups have another, less-powerful kind of AIDS resistance. In the Science study released this week, a large team of investigators report that people who have more copies of a specific gene end up with greater resistance to AIDS, in some cases significantly changing how they handle getting infected.
The researchers examined the number of copies of a gene known as CCL3L1 in 4,300 people -- some HIV-positive, some HIV-negative. Those with the most copies of the gene -- but only as compared with others in their ethnic group -- had the most immunity to HIV. The HIV-positive people with the fewest gene copies got sick as much as 2.6 times faster than others who were infected.
More copies of the CCL3L1 gene appear to translate into more proteins known as cytokines, which guide immune cells by latching onto receptors -- those cellular locks. The cytokines "tell inflammatory cells it's time to move and go somewhere," Mosier said. With more cytokines floating around gumming up the cellular keyholes, there are fewer locks for the AIDS virus to pick.
Compared with the almost-absolute protection afforded by the gene defects in Europeans, "the effect is not as complete, but the prevalence is much higher," said study co-author Dr. Sunil K. Ahuja, professor of medicine at the University of Texas and director of the Veterans Administration Center for HIV and AIDS in San Antonio.
What can scientists and doctors do with all this information? Doctors could potentially test AIDS patients to see if their genes make them especially vulnerable to progression of the disease, Ahuja said. "This hasn't happened yet, and we aren't there yet. But that would be some practical downstream value of the work we are doing."
Then there's the prospect that people will use genetic testing as a ticket to a carefree sex life. If you're naturally resistant to AIDS, why not dump the condoms and add a few notches to your bedpost?
The Scripps Research Institute's Mosier has gotten calls from curious citizens wondering about their genes. But don't go running to your nearest genetic laboratory just yet. For one thing, researchers aren't sure whether the protective genes both giveth and taketh away: Perhaps they make people more resistant to AIDS but also make them more vulnerable to other germs.
Then there's the pesky matter of the few people who have gotten infected with HIV even though they're supposed to be immune. "It's extremely rare," Mosier said, "but you don't want to tell people they'll be protected and then have them change their risk behavior and get exposed."
For now, the findings seem likely to inspire more raised eyebrows than cutting-edge drugs. But over time, the research into why some people don't get HIV may help doctors treat those who do. By understanding which genes help people fight off infection, "we might move to a time where we can make more refined decisions about timing or intensity of therapy. Now, it's like a glove where one size fits all," said Dr. Matthew Dolan, an AIDS specialist in the U.S. Air Force and co-author of a new AIDS genetics study in an online edition of the journal Science.
Genetic resistance to AIDS works in different ways and appears in different ethnic groups. The most powerful form of resistance, caused by a genetic defect, is limited to people with European or Central Asian heritage. An estimated 1 percent of people descended from Northern Europeans are virtually immune to AIDS infection, with Swedes the most likely to be protected. One theory suggests that the mutation developed in Scandinavia and moved southward with Viking raiders.
All those with the highest level of HIV immunity share a pair of mutated genes -- one in each chromosome -- that prevent their immune cells from developing a "receptor" that lets the AIDS virus break in. If the so-called CCR5 receptor -- which scientists say is akin to a lock -- isn't there, the virus can't break into the cell and take it over.
To be protected, people must inherit the genes from both parents; those who inherit a mutated gene from just one parent will end up with greater resistance against HIV than other people, but they won't be immune. An estimated 10 percent to 15 percent of those descended from Northern Europeans have the lesser protection.
Using formulas that estimate how long genetic mutations have been around, researchers have discovered that the mutation dates to the Middle Ages. (Similar research in mitochondrial DNA -- passed along by women -- has suggested that Europeans are all descended from seven Ice Age matriarchs.)
Why would the mutation stick around so long instead of giving up the ghost? Researchers initially thought the mutation provided protection against the bubonic plague that caused the Black Death in Europe. Those with the mutation would have lived longer and had more children while many of their neighbors died off. The fact that the genetic mutation also provided protection against HIV centuries later would just be a coincidence.
The plague scenario has been largely discarded in favor of another deadly scourge. "A disease like smallpox that has been continuous since that time ... is more likely," said Yale University professor of epidemiology Alison Galvani, who co-wrote a study about the possible smallpox link in 2003.
According to Galvani, while the plague came and went, smallpox stuck around well into the 20th century, providing even more incentive for a protective gene to live on: It would keep people alive generation after generation, instead of just during one brief epidemic.
There are other cases of genetic mutations affecting two diseases: People who inherit one of the two mutations necessary to develop sickle-cell anemia end up with extra resistance to malaria, said Dr. Donald Mosier, professor of immunology at The Scripps Research Institute in La Jolla, California.
Last February, Mosier co-wrote a report in the journal Nature that debunked the plague theory after researchers found that mice bred with the AIDS-protective gene mutation still got sick with the plague. Mosier's not quite sure smallpox deserves credit for extending the mutation's life either, however, and suspects that a less high-profile disease -- diarrhea-causing dysentery -- may be why the mutation has lived on.
Besides the Northern Europeans and Central Asians with the CCR5 receptor gene mutation, new research shows that members of several ethnic groups have another, less-powerful kind of AIDS resistance. In the Science study released this week, a large team of investigators report that people who have more copies of a specific gene end up with greater resistance to AIDS, in some cases significantly changing how they handle getting infected.
The researchers examined the number of copies of a gene known as CCL3L1 in 4,300 people -- some HIV-positive, some HIV-negative. Those with the most copies of the gene -- but only as compared with others in their ethnic group -- had the most immunity to HIV. The HIV-positive people with the fewest gene copies got sick as much as 2.6 times faster than others who were infected.
More copies of the CCL3L1 gene appear to translate into more proteins known as cytokines, which guide immune cells by latching onto receptors -- those cellular locks. The cytokines "tell inflammatory cells it's time to move and go somewhere," Mosier said. With more cytokines floating around gumming up the cellular keyholes, there are fewer locks for the AIDS virus to pick.
Compared with the almost-absolute protection afforded by the gene defects in Europeans, "the effect is not as complete, but the prevalence is much higher," said study co-author Dr. Sunil K. Ahuja, professor of medicine at the University of Texas and director of the Veterans Administration Center for HIV and AIDS in San Antonio.
What can scientists and doctors do with all this information? Doctors could potentially test AIDS patients to see if their genes make them especially vulnerable to progression of the disease, Ahuja said. "This hasn't happened yet, and we aren't there yet. But that would be some practical downstream value of the work we are doing."
Then there's the prospect that people will use genetic testing as a ticket to a carefree sex life. If you're naturally resistant to AIDS, why not dump the condoms and add a few notches to your bedpost?
The Scripps Research Institute's Mosier has gotten calls from curious citizens wondering about their genes. But don't go running to your nearest genetic laboratory just yet. For one thing, researchers aren't sure whether the protective genes both giveth and taketh away: Perhaps they make people more resistant to AIDS but also make them more vulnerable to other germs.
Then there's the pesky matter of the few people who have gotten infected with HIV even though they're supposed to be immune. "It's extremely rare," Mosier said, "but you don't want to tell people they'll be protected and then have them change their risk behavior and get exposed."
Nazjaz
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jackson kanene
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- Jan 7, 2012
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Hii inaukweli jaman msibishe! Mimi mwenyewe ilikwisha wahi kunipata,mwaka 02 nikiwa nyumbani mugumu-serengeti nilikuwa na mahusiano na dada m1 askari magereza akiitwa Mariam seif,nilikuwa na Mahusiano naye kwa kipindi cha miez 9 kumbe yule dada ni muathirika wa virus na hakuwahi kuniambia kabla na mbaya ckuwahi kuvaa condom katika mahusiano yetu, baadae inssue ilienea kuwa yule dada ni muathirika ilinifedhehesha xana na cha ajabu yeye mwenyewe alikiri kwangu kuwa pesa alizokuwa akinipa ni za kununulia sanda kwani anajijua na amekwisha niua cha ajabu hata nyumbani walianza kuninyanyapaa hadi kutengewa vyombo vya chakula ili nisiwaambukize,shuleni pia ilikuwa kasheshe kwani nilikuwa sec pindi hicho pale kisangura,walimu kwa wanafunzi baadhi walionyesha ubaguzi na unyanyapaa waziwazi, kituko ni kwamba,niliamua baada ya kusitisha mahusiano na yule Askari magereza nilianzisha mahusiano na baamed ambaye naye alikuwa ni mwathirika kwa lengo la kujipoza na machungu kwani 2liambiana sote ni carries! Mungu wa ajabu mwaka 05,miaka mi3 baadae nikiwa cjaona dariri za ugonjwa mwilini kwangu na pindi hicho huyo baamed kesha fariki nilipata ujasiri wa kwenda kupima na nikajikuta Negative! Ckuamini matokeo ikabidi niende mwanza kuludia vpmo napo nilienda Angaza nikajikuta mzima,nikajiuliza imekuwaje? Kwani ngono niliyofanya na hao waathirika si salama ictoshe 2likuwa 2kinyonyana sehemu za siri?na ajabu zaidi mwaka 07 nilipata kuondoka na kwenda kufanya kazi kwa mzungu m1 huko porini sharti ni kupimwa damu nilikubali na kupimwa nikaonekana niko fit,baada ya kufanya kazi kwake kwa muda sasa akanipa sponsser ya kusomea ujuzi wa ndege ambayo ni kazi ninayoifanya hadi leo je vjana hamtaki kuamini? Mimi ni mzima kbsa na ninajuta kwa kutaka kujiangamiza maksdi ,damu yangu ni group 0 ve,ulefu ni cm 182.5, nilitahiriwa kimira mwaka 98,ukitaka kujua chochote kuhusu mimi ni pm nitakwambia.
Heaven on Earth
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jackson kanene
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nikweli yakupasa uamini nimeamua kuwaambieni ukweli kuhusu mimi na Maisha yangu.
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Heaven on Earth
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jackson kanene
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- Jan 7, 2012
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kuna watu wameumbiwa ubishi na wanaweza kubisha, lakini nayasema haya toka moyoni mwangu Mimi ni msabato na leo ni siku ya maandalio,ni kwamba kama kuna m2 aliyewahi kuishi wilaya ya serengeti,pale mugumu mjini naweza kutoa ushahidi kwake wa maisha yangu kwani ni kuanzia 2002 hadi 2007,hadi xaxa wengi wananiona kama nina bahati bt ni meamini 2po wachache dunia hii 2lio barikiwa! Kwani hata magonjwa ya kichwa na maralia kwangu huwa ni mala moja kwa mwaka mzima tena dec,mwezi niliozaliwa namshukuru mungu kwa hili.
jackson kanene
Member
- Jan 7, 2012
- 92
- 27
shukrani za pekee kwa Mwenyezi mungu muumba mbingu na ardhi,kuna pindi nilikata tamaa na maisha bt usilolijua.....
jackson kanene
Member
- Jan 7, 2012
- 92
- 27
teh teh teh' Sangarara ,kwani kwa wasabato hakuna wazinzi na Washerati?tena nilikuwa sec mwana Assa' bt kwa xaxa nimebadilika najitambua!
Tutor B
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- Jun 11, 2011
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kwa hiyo sasa hivi hugongi hiyo kitu?
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