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41.
Intervention with mesenchymal stem cells (MSCs) represents a promising therapeutic tool in treatment-refractory autoimmune
diseases. A new report by Schurgers and colleagues in a previous issue of Arthritis Research & Therapy sheds novel mechanistic insight into the pathways employed by MSCs to suppress T-cell proliferation in vitro, but, at the same time, indicates that MSCs do not influence T-cell reactivity and the disease course in an in vivo arthritis model. Such discrepancies between the in vitro and in vivo effects of potent cellular immune modulators should spark further research and should be interpreted as a sign of caution
for the in vitro design of MSC-derived interventions in the setting of human autoimmune diseases. 相似文献
42.
Mishra RS Gu Y Bose S Verghese S Kalepu S Singh N 《The Journal of biological chemistry》2002,277(27):24554-24561
A familial prion disorder with a proline to leucine substitution at residue 102 of the prion protein (PrP(102L)) is typically associated with protease-resistant PrP fragments (PrP(Sc)) in the brain parenchyma that are infectious to recipient animals. When modeled in transgenic mice, a fatal neurodegenerative disease develops, but, unlike the human counterpart, PrP(Sc) is lacking and transmission to recipient animals is questionable. Alternate mice expressing a single copy of PrP(102L) (mouse PrP(101L)) do not develop spontaneous disease, but show dramatic susceptibility to PrP(Sc) isolates from different species. To understand these discrepant results, we studied the biogenesis of human PrP(102L) in a cell model. Here, we report that cells expressing PrP(102L) show decreased expression of the normal 18-kDa fragment on the plasma membrane. Instead, a 20-kDa fragment, probably derived from transmembrane PrP ((Ctm)PrP), accumulates on the cell surface. Because the 20-kDa fragment includes an amyloidogenic region of PrP that is disrupted in the 18-kDa form, increased surface expression of 20-kDa fragment may enhance the susceptibility of these cells to PrP(Sc) infection by providing an optimal substrate, or by amplifying the neurotoxic signal of PrP(Sc). Thus, altered susceptibility of PrP(101L) mice to exogenous PrP(Sc) may be mediated by the 20-kDa (Ctm)PrP fragment, rather than PrP(102L) per se. 相似文献
43.
44.
Geometry of tapered fiber sensors critically affects the response of an evanescent field sensor to cell suspensions. Single-mode fibers (nominally at 1300 nm) were tapered to symmetric or asymmetric tapers with diameters in the range of 3–20 μm, and overall lengths of 1–7 mm. Their transmission characteristics in air, water and in the presence of Escherichia coli (JM101 strain) at concentrations of 100, 1000, 7000 and 7 million cells/mL were measured in the 400–800 nm range and gave rich spectral data that lead to the following conclusions. (1) No change in transmission was observed due to E. coli with tapers that showed no relative change in transmission in water compared to air. (2) Tapers that exhibited a significant difference in transmission in water compared to air gave weak response to the presence of the E. coli. Of these, tapers with low waist diameters (6 μm) showed sensitivity to E. coli at 7000 cells/mL and higher concentration. (3) Tapers that showed modest difference in water transmission compared to air, and those that had small waist diameters gave excellent response to E. coli at 100–7000 cells/mL. In addition, mathematical modeling showed that: (1) at low wavelength (470 nm) and small waist diameter (6 μm), transmission with water in the waist region is higher than in air. (2) Small changes in waist diameter (0.05 μm) can cause larger changes in transmission at 470 nm than at 550 nm at waist diameter of 6 μm. (3) For the same overall geometry, a 5.5 μm diameter taper showed larger refractive index sensitivity compared to a 6.25 μm taper at 470 nm. 相似文献
45.
46.
Huma N Shankar P Kushwah J Bhushan A Joshi J Mukherjee T Raju S Purohit HJ Kalia VC 《Journal of microbiology and biotechnology》2011,21(10):1001-1011
To explore bacterial diversity for elucidating genetic variability in acylhomoserine lactone (AHL) lactonase structure, we screened 800 bacterial strains. It revealed the presence of a quorum quenching (QQ) AHL-lactonase gene (aiiA) in 42 strains. These 42 strains were identified using rrs (16S rDNA) sequencing as Bacillus strains, predominantly B. cereus. An in silico restriction endonuclease (RE) digestion of 22 AHL lactonase gene (aiiA) sequences (from NCBI database) belonging to 9 different genera, along with 42 aiiA gene sequences from different Bacillus spp. (isolated here) with 14 type II REs, revealed distinct patterns of fragments (nucleotide length and order) with four REs; AluI, DpnII, RsaI, and Tru9I. Our study reflects on the biodiversity of aiiA among Bacillus species. Bacillus sp. strain MBG11 with polymorphism (115Alanine > Valine) may confer increased stability to AHL lactonase, and can be a potential candidate for heterologous expression and mass production. Microbes with ability to produce AHL-lactonases degrade quorum sensing signals such as AHL by opening of the lactone ring. The naturally occurring diversity of QQ molecules provides opportunities to use them for preventing bacterial infections, spoilage of food, and bioremediation. 相似文献
47.
Summary Amyloglucosidase (exo-1, 4- -D-glucosidase, EC 3.2.1.3), was coupled to glutaraldehyde activated Indion 48-R (a cross-linked macroporous anion exchanger) by Schiff base reaction. Immobilization brought about a marginal increase in the apparent Km. The bound enzyme exhibited increased stability towards urea and metal ions, but was less stable in the presence of guanidine hydrochloride. Immobilized amyloglucosidase could be stored at 4°C (in wet state) for 6–8 months without any apparent loss of activity. 相似文献
48.
Jelicks LA Chandra M Shirani J Shtutin V Tang B Christ GJ Factor SM Wittner M Huang H Weiss LM Mukherjee S Bouzahzah B Petkova SB Teixeira MM Douglas SA Loredo ML D'Orleans-Juste P Tanowitz HB 《International journal for parasitology》2002,32(12):1497-1506
Chagas' disease is an important cause of cardiomyopathy. Endothelin-1, a vasoactive peptide has been implicated in the pathogenesis of chagasic cardiomyopathy. C57BL/6 x 129sv and CD1 mice were thus, infected with trypomastigotes of Trypanosoma cruzi (Brazil strain) and these infected mice were compared with infected mice treated with phosphoramidon. This compound inhibits endothelin-converting enzyme and neutral endopeptidases and does not affect the growth of the parasite in culture. Phosphoramidon was given in a dose of 10mg/kg for the initial 15 days post-infection None of the C57Bl/6 x 129sv mice died as a result of infection. However, there was marked myocardial inflammation and fibrosis in infected, untreated mice. The hearts of the infected, phosphoramidon-treated mice showed significantly less pathology. Cardiac magnetic resonance imaging of infected mice revealed right ventricular dilation that was less severe in those treated with phosphoramidon. Phosphoramidon-treated CD1 mice survived the acute infection. Transthoracic echocardiography demonstrated left ventricular dilation and reduced percent fractional shortening and relative wall thickness. These alterations were also attenuated as a result of phosphoramidon treatment. These data suggest that endothelin-1 contributes to the pathogenesis of chagasic cardiomyopathy and interventions that inhibit the synthesis of endothelin-1 and/or neutral endopeptidase might have a protective effect on myocardial structure and function in murine Chagas' disease. 相似文献
49.
Interfering with disease: opportunities and roadblocks to harnessing RNA interference 总被引:22,自引:0,他引:22
RNA interference (RNAi) is an evolutionarily conserved mechanism for silencing gene expression by targeted degradation of mRNA. Short double-stranded RNAs, known as small interfering RNAs (siRNA), are incorporated into an RNA-induced silencing complex that directs degradation of RNA containing a homologous sequence. RNAi has been shown to work in mammalian cells, and can inhibit viral infection and control tumor cell growth in vitro. Recently, it has been shown that intravenous injection of siRNA or of plasmids expressing sequences processed to siRNA can protect mice from autoimmune and viral hepatitis. RNAi could provide an exciting new therapeutic modality for treating infection, cancer, neurodegenerative disease and other illnesses. 相似文献
50.
Rachel Knevel Diederik PC de Rooy Tore Saxne Elisabet Lindqvist Martha K Leijsma Nina A Daha Bobby PC Koeleman Roula Tsonaka Jeanine J Houwing-Duistermaat Joris JM Schonkeren Rene EM Toes Tom WJ Huizinga Elisabeth Brouwer Anthony G Wilson Annette HM van der Helm-van Mil 《Arthritis research & therapy》2014,16(3):R108