Tuesday, 14 March 2017

Eurycoma longifolia dược liệu kháng Hep G2 (tế bào gây ung thư gan), A549 (tế bào adenocarcinomic nhân phế nang đấy biểu mô), HT1080 (tế bào fibrosarcoma), MCF-7 (tế bào gây ung thư vú), HeLa (tế bào gây ung thư cổ tử cung)


Eurycoma longifolia-mật nhân

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Eurycoma longifolia ou Tongkat Ali ou est une espèce de plante de la famille des Simaroubaceae, de Malaisie et d'Indonésie et dans une moindre mesure de Thaïlande, Vietnam et Laos. Elle est aussi connue sous les noms de penawar pahitpenawar biasbedara merahbedara putihlempedu pahitpayong alitongkat bagindamuntah bumipetala bumi (nom Malais); bidara laut (Indonésien); babi kurus (Javanais); cây bá bệnh (Vietnamien) and tho nan (Laotien)1.
Beaucoup de ces noms font allusion à son usage médical ainsi qu'à son extrême amertume. Penawar pahit se traduit simplement par "sortilège amer" ou "médicament amer".

Description[modifier | modifier le code]

Un arbuste mince de taille moyenne atteignant 10 m de haut souvent sans branche avec des pétioles rouge brun.
Des feuilles imparipennées atteignant un mètre de longueur. Chaque feuille composée de 30 à 40 folioles lancéolés à obovales-lancéolées. Chaque foliole mesure de 5 à 20 cm de long, 1.5 à 6 cm de large, beaucoup plus pâle sur la face inférieure. L'inflorescence est axillaire en grand panicules rouge tirant sur le brun, très pubescente avec de petits trichomes glandulaires. Les fleurs sont hermaphrodites munies de petits pétales très finement pubescent. Le fruit est une drupe dure ovoïde jaune brun lorsqu'elle est jeune et rouge brun lorsqu'elle est mûre.

Médecine Populaire[modifier | modifier le code]

Une étude d'ethnopharmacologie de 2010 sur E. longifolia conclu que: "Les différentes parties de cette plante ont été traditionnellement utilisées pour ses propriétés antimalaria, aphrodisiaque, antidiabétique antimicrobienne et antipyrétique..."2

Effets biologiques[modifier | modifier le code]

D'après le site américain WebMD, bien que des études suggèrent qu'une préparation de E. longifolia puisse avoir un rôle dans l'amélioration de la qualité du sperme, les études pour montrer son rôle dans les autres traitements cancer, malaria et tuberculose sont très insuffisantes3.

Produits élaborés à partir de[modifier | modifier le code]

Généralités[modifier | modifier le code]

En Malaisie, l'usage le plus fréquent de E. longifolia est d'être un additif pour les boissons et nourritures. En particulier, c'est une additif fréquent pour le café et les boissons qui se disent énergétiques.
Si l'on tient compte de l'abondance et du faible coût des herbes (opposé au prix élevé de composants extraits de E. longifolia), on peut en déduire une proportion non négligeables de produits qui ne contiennent pas du tout de E. longifolia. Un nez électronique, détectant la présence et la concentration en quassinoïdes a été développé pour déterminer l'utilisation du vrai E. longifolia4.
Les quassinoides qui sont les composants biologiquement actif de la racine de E. longifolia5,6,7 , sont extrêmement amers. Leur nom tire son origine de la quassine, le principe amer tiré de l'arbre Quassia. La quassine est connue pour être la substance la plus amère à l'état naturel 50 fois plus amère que la quinine8.

Falsification[modifier | modifier le code]

Le USFDA a interdit de nombreux produits comme le Libidus9, qui mentionne E. longifolia comme ingrédient principal, mais qui à la place est un mélange de droques à prescritpion illégale, ou même pire de drogues dont l'inocuité n'a jamais été testé pour les hommes, tel que l'acetildenafil10.
En février 2009, La FDA a lancé un avertissement contre 30 suppléments pour l'amélioration sexuelle11 , mais les noms de ces produits change plus vite que le temps nécessaire aux enquêtes FDA. Le Libidus par exemple, est maintenant vendu sous le nom de Maxidus, en indiquant toujours E. longifolia (tongkat ali) comme ingrédient principal12.
Le gouvernement de Malaisie a interdit des produits contrefaits qui utilisent le citrate sildenafil à la place de tongkat ali dans leur capsule.

Monday, 13 March 2017

HEK 293 (tế bào phôi nhân thận)

HEK 293 cells - tế bào phôi nhân thận

From Wikipedia, the free encyclopedia
  (Redirected from HEK 293)
HEK 293 cells grown for several days in standard tissue culture medium.
Human embryonic kidney cells 293, also often referred to as HEK 293HEK-293293 cells, or less precisely as HEK cells, are a specific cell line originally derived from human embryonic kidney cells grown in tissue culture. HEK 293 cells have been widely used in cell biology research for many years, because of their reliable growth and propensity for transfection. They are also used by the biotechnology industry to produce therapeutic proteins and viruses for gene therapy.

History[edit]

HEK 293 cells were generated in 1973 by transformation of cultures of normal human embryonic kidney cells with sheared adenovirus 5 DNA in Alex van der Eb's laboratory in Leiden, the Netherlands. The cells were obtained from a single, apparently healthy, legally aborted fetus under Dutch law; the identity of the mother and the reason for the abortion are unknown.[1] The cells were cultured by van der Eb; the transformation by adenovirus was performed by Frank Graham, a post-doc in van der Eb's lab. They were published in 1977 after Graham left Leiden for McMaster University.[2] They are called HEK since they originated in human embryonic kidney cultures, while the number 293 came from Graham's habit of numbering his experiments; the original HEK 293 cell clone was from his 293rd experiment. Graham performed the transformation a total of eight times, obtaining just one clone of cells that were cultured for several months. After presumably adapting to tissue culture, cells from this clone developed into the relatively stable HEK 293 line.
Subsequent analysis has shown that the transformation was brought about by inserting ~4.5 kilobases from the left arm of the viral genome, which became incorporated into human chromosome 19.[3]
For many years it was assumed that HEK 293 cells were generated by transformation of either a fibroblasticendothelial or epithelial cell, all of which are abundant in kidneys. However, the original adenovirus transformation was inefficient, suggesting that the cell that finally produced the HEK 293 line may have been unusual in some fashion. Graham and coworkers provided evidence that HEK 293 cells and other human cell lines generated by adenovirus transformation of human embryonic kidney cells have many properties of immature neurons, suggesting that the adenovirus preferentially transformed a neuronal lineage cell in the original kidney culture.[4]
A comprehensive study of the genomes and transcriptomes of HEK 293 and five derivative cell lines compared the HEK 293 transcriptome with that of human kidney, adrenal, pituitary and central nervous tissue.[5] The HEK 293 pattern most closely resembled that of adrenal cells, which have many neuronal properties. Given the location of the adrenal gland (adrenal means "next to the kidney"), a few adrenal cells could plausibly have appeared in an embryonic kidney derived culture, and could be preferentially transformed by adenovirus. Adenovirus transforms neuronal lineage cells much more efficiently than typical human kidney epithelial cells.[4] An embryonic adrenal precursor cell therefore seems the most likely origin cell of the HEK 293 line. As a consequence, HEK 293 cells should not be used as an in vitro model of typical kidney cells.
HEK 293 cells have a complex karyotype, exhibiting two or more copies of each chromosome and with a modal chromosome number of 64. They are described as hypotriploid, containing less than three times the number of chromosomes of a normal diploid human cell. Chromosomal abnormalities include a total of three copies of the X chromosome and four copies of chromosome 17 and chromosome 22.[5][6] The presence of multiple X chromosomes and the lack of any trace of Y chromosome derived sequence suggest that the source fetus was female.

Applications[edit]

Immunofluorescent HEK 293 cells
HEK 293 cells are straightforward to grow in culture and to transfect. They have been used as hosts for gene expression. Typically, these experiments involve transfecting in a gene (or combination of genes) of interest, and then analyzing the expressed protein. The widespread use of this cell line is due to its transfectability by the various techniques, including calcium phosphate method, achieving efficiencies approaching 100%.
Examples of such experiments include:
A more specific use of HEK 293 cells is in the propagation of adenoviral vectors. Viruses offer an efficient means of delivering genes into cells, which they evolved to do, and are thus of great use as experimental tools. However, as pathogens, they also present a risk to the experimenter. This danger can be avoided by the use of viruses which lack key genes, and which are thus unable to replicate after entering a cell. In order to propagate such viral vectors, a cell line that expresses the missing genes is required. Since HEK 293 cells express a number of adenoviral genes, they can be used to propagate adenoviral vectors in which these genes (typically, E1 and E3) are deleted, such as AdEasy.[12]
An important variant of this cell line is the 293T cell line. It contains the SV40 Large T-antigen that allows for episomal replication of transfected plasmids containing the SV40 origin of replication. This allows for amplification of transfected plasmids and extended temporal expression of desired gene products. Note that any similarly modified cell line can be used for this sort of work; HeLaCOS and Chinese Hamster Ovary cell are common alternatives.[citation needed] HEK 293, and especially HEK 293T, cells are commonly used for the production of various retroviral vectors. Various retroviral packaging cell lines are also based on these cells.

H1299 (tế bào ung thư biểu mô tuyến phổi)

H1299-tế bào ung thư biểu mô tuyến phổi

From Wikipedia, the free encyclopedia
H1299, also known as NCI-H1299[1][2] or CRL-5803,[3] is a human non-small cell lung carcinoma cell line derived from the lymph node, which is widely used in research.[4]
As with other immortalized cell lines, H1299 cells can divide indefinitely. These cells have a homozygous partial deletion of the TP53 gene and as a result, do not express the tumor suppressor p53 protein which in part accounts for their proliferative propensity.[5] These cells have also been reported to secrete the peptide hormone neuromedin B (NMB), but not gastrin releasing peptide (GRP).[4]

H295R (tế bào vỏ thượng thận)

H295R-tế bào vỏ thượng thận

From Wikipedia, the free encyclopedia
H295R (also referred to as NCI-H295R) is an angiotensin-II-responsive steroid-producing adrenocortical cell line.[1] It was initially isolated in 1980 from a 48-year-old female patient diagnosed with adrenocortical carcinoma.[1][2] The initial polyclonal populations of tumor cells obtained from the patients' tumor were cultured and the resultant cell line was called NCI-H295.[1][2] Because of slow growth rates and easy detachment of the original NCI-H295 strains, efforts were made to select a population of cells with better monolayer attachment and more rapid growth.[1] Three strains were developed, based on the serum supplement used for growth, which have been termed H295R-S1, H295R-S2 and H295R-S3.[1][3] All three strains grow as adherent monolayer cultures.[1]

BOSC23 (tế bào thận)

BOSC23 - tế bào thận

From Wikipedia, the free encyclopedia
BOSC 23 is a human kidney cell line developed by Warren Pear in David Baltimore's lab [1] and is derived from the 293T cell line.[2] The main use of BOSC 23 is the production of recombinant retroviruses; it stably expresses Moloney murine leukemia virus proteins and when transiently transfected with recombinant retroviral vector DNA will produce high titers of infectious retroviral particles. The cell line does not produce detectable replication-competent virus, an important safety feature.
BOSC 23 carries neomycin/G418 resistance derived from its parental line 293T, and also hygromycin and mycophenolic acid (gpt) resistance. It should be maintained under gpt selection.
This cell line is a model for cancer research which doesn't express activated Src protein.[3]

BCP-1 (tế bào lympho)

BCP-1 cells -tế bào lympho

From Wikipedia, the free encyclopedia
BCP-1 cells are a clonal lymphoma cell line. They were derived from the peripheral blood mononuclear cells of a HIV seronegative patient with a body cavity based primary effusion lymphoma (PEL). BCP-1 cells are positive for KSHV, but negative for EBV. The cell line is used extensively for KSHV serologic assays and epidemiologic studies as well as other KSHV laboratory studies such as KSHV reactivation from latency with TPA or ectopic expression of KSHV ORF 50. BCP-1 has been deposited to ATCC by the creators for public use in research: http://www.atcc.org/common/catalog/numSearch/numResults.cfm?atccNum=CRL-2294.

References and notes[edit]

  • Gao SJ, Kingsley L, Li M, Zheng W, Parravicini C, Ziegler J, Newton R, Rinaldo CR, Saah A, Phair J, Detels R, Chang Y, Moore PS (1996). "KSHV antibodies among Americans, Italians and Ugandans with and without Kaposi's sarcoma.". Nat Med2 (8): 925–8. doi:10.1038/nm0896-925PMID 8705864.
  • Boshoff C, Gao SJ, Healy LE, Matthews S, Thomas AJ, Coignet L, Warnke RA, Strauchen JA, Matutes E, Kamel OW, Moore PS, Weiss RA, Chang Y (1998). "Establishing a KSHV+ cell line (BCP-1) from peripheral blood and characterizing its growth in Nod/SCID mice.". Blood91 (5): 1671–9. PMID 9473233.

SKBR3 (tế bào)

SKBR3 - tế bào

From Wikipedia, the free encyclopedia
SkBr3 is a cell line isolated by the Memorial Sloan–Kettering Cancer Center in 1970. It was derived from a pleural effusion due to an adenocarcinoma originating in the breast of a 43-year-old, caucasian female. The cell line over-expresses the HER2 gene product. [1]
The SkBr3 line is synonymous(derived from the same patient) with the AU565 cell line.[2]
The SkBr3 cell line has been used in studies seeking to overcome Herceptin resistance to HER2-overexpressing breast cancer.[3]
The cells are considered biosafety level 1.[1]