Orthodontic Rare Earth Magnets—In Vitro Assessment of Cytotoxicity

1994 ◽  
Vol 21 (4) ◽  
pp. 335-341 ◽  
Author(s):  
Lars Bondemark ◽  
Jüri Kurol ◽  
Alf Wennberg

The aim of this study was to assess and compare in vitro the cytotoxic effects of uncoated and parylene-coated rare earth magnets, used in orthodontics. Cytotoxicity of samarium-cobalt magnets (SmCo5 and Sm2Co17) and neodymium-iron-boron magnets (Nd2Fe14B) was assessed by two in vitro methods, the millipore filter method and an extraction method. Orthodontic stainless steel brackets served as controls. Uncoated SmCo5-magnets showed high cytotoxicity while uncoated Sm2Co17-magnets demonstrated moderate cytotoxicity. Uncoated neodymium-iron-boron magnets, as well as parylene coated Sm2Co17-magnets and parylene-coated neodymium-iron-boron magnets, showed negligible cytotoxicity. Short-term exposure to a static magnetic field did not cause any cytotoxic effect on the cells.

1976 ◽  
Vol 36 (01) ◽  
pp. 221-229 ◽  
Author(s):  
Charles A. Schiffer ◽  
Caroline L. Whitaker ◽  
Morton Schmukler ◽  
Joseph Aisner ◽  
Steven L. Hilbert

SummaryAlthough dimethyl sulfoxide (DMSO) has been used extensively as a cryopreservative for platelets there are few studies dealing with the effect of DMSO on platelet function. Using techniques similar to those employed in platelet cryopreservation platelets were incubated with final concentrations of 2-10% DMSO at 25° C. After exposure to 5 and 10% DMSO platelets remained discoid and electron micrographs revealed no structural abnormalities. There was no significant change in platelet count. In terms of injury to platelet membranes, there was no increased availability of platelet factor-3 or leakage of nucleotides, 5 hydroxytryptamine (5HT) or glycosidases with final DMSO concentrations of 2.5, 5 and 10% DMSO. Thrombin stimulated nucleotide and 5HT release was reduced by 10% DMSO. Impairment of thrombin induced glycosidase release was noted at lower DMSO concentrations and was dose related. Similarly, aggregation to ADP was progressively impaired at DMSO concentrations from 1-5% and was dose related. After the platelets exposed to DMSO were washed, however, aggregation and release returned to control values. Platelet aggregation by epinephrine was also inhibited by DMSO and this could not be corrected by washing the platelets. DMSO-plasma solutions are hypertonic but only minimal increases in platelet volume (at 10% DMSO) could be detected. Shrinkage of platelets was seen with hypertonic solutions of sodium chloride or sucrose suggesting that the rapid transmembrane passage of DMSO prevented significant shifts of water. These studies demonstrate that there are minimal irreversible alterations in in vitro platelet function after short-term exposure to DMSO.


1976 ◽  
Vol 21 (3) ◽  
pp. 553-561
Author(s):  
M.A. Ricard ◽  
R.J. Hay

Primary epithelial populations (HAM) were obtained by dissociation of the amniotic membrane stripped from human placentae. Agglutinability of cells from such normal populations and of cells from the transformed epithelial line WISH was then compared using concavanalin A as mediator. Extensive similar studies have previously been reported with cell strains isolated from other species. Freshly dissociated HAM cells from primary cultures agglutinated much less readily than did cells from WISH populations. Furthermore, the former exhibited a drastic decline in agglutinability as a function of time in suspension culture after trypsinization. Short-term exposure (60 h) of HAM cells in monolayer culture to 5-bromodeoxyuridine (BrdU) elicited heightened agglutinability detectable through 22 days in vitro. Addition of the protease inhibitors n-tosyl-L-lysyl-chloromethyl ketone (TLCK) or p-tosyl-L-arginine-methyl ester (TAME) to the culture medium inhibited proliferation of the WISH line by 40–50% while effecting only a 10–15% inhibition of HAM cells. These results also confirm data with other cell species indicating that high proteolytic activity at the surface of transformed cells may be related to the rapid proliferation rate.


2021 ◽  
Author(s):  
Peace C. Asuzu ◽  
Alberta N.A. Aryee ◽  
Nicholas Trompeter ◽  
Yasmin Mann ◽  
Samuel A. Besong ◽  
...  

AbstractPhenolic compounds are products of secondary plant metabolism known for their biological activity including their antimicrobial, antioxidant, analgesic, stimulant, anti- carcinogenic, and aphrodisiac properties. The main objective of this study was to assess the potency/cytotoxic effects of Prunus africana extracts on prostate cancer cells in vitro. Using different concentrations of P. africana extracts, prostate cancer C4-2 cells, a hormonally insensitive subline of LNCaP cells, were treated in a proliferation assay. A concentration dependent inhibition of cell growth in cells treated with P. africana bark and root extracts was present from days 1 through 3 of incubation, with the methanol extract of the bark showing the strongest effect. Compared to other plant parts, leaf extracts were significantly less cytotoxic at the same concentrations. As C4-2 cells are hormonally insensitive and designed to mimic advanced prostate cancer, crude extracts of P. africana are a possible treatment option, not only for hormone sensitive prostate cancer, but also advanced, hormonally insensitive prostate cancer.


2016 ◽  
Vol 15 (4) ◽  
Author(s):  
L.A. Cunha ◽  
T.C. Mota ◽  
P.C.S. Cardoso ◽  
D.D.F.A. Alcântara ◽  
R.M.R. Burbano ◽  
...  

2010 ◽  
Vol 188 (3) ◽  
pp. 558-565 ◽  
Author(s):  
Imane Abbas ◽  
Guillaume Garçon ◽  
Françoise Saint-Georges ◽  
Sylvain Billet ◽  
Anthony Verdin ◽  
...  

2016 ◽  
Vol 147 ◽  
pp. 146-158 ◽  
Author(s):  
Imane Abbas ◽  
Anthony Verdin ◽  
Fabienne Escande ◽  
Françoise Saint-Georges ◽  
Fabrice Cazier ◽  
...  

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Emmanuel Mouafo Tekwu ◽  
Kwabena Mante Bosompem ◽  
William Kofi Anyan ◽  
Regina Appiah-Opong ◽  
Kofi Baffour-Awuah Owusu ◽  
...  

Schistosomiasis is a Neglected Tropical Diseases which can be prevented with mass deworming chemotherapy. The reliance on a single drug, praziquantel, is a motivation for the search of novel antischistosomal compounds. This study investigated the anthelmintic activity of the stem bark and roots ofRauwolfia vomitoriaagainst two life stages ofSchistosoma mansoni. Both plant parts were found to be active against cercariae and adult worms. Within 2 h of exposure all cercariae were killed at a concentration range of 62.5–1000 µg/mL and 250–1000 µg/mL ofR. vomitoriastem bark and roots, respectively. The LC50values determined for the stem bark after 1 and 2 h of exposure were 207.4 and 61.18 µg/mL, respectively. All adult worms exposed to the concentrations range of 250–1000 µg/mL for both plant parts died within 120 h of incubation. The cytotoxic effects against HepG2 and Chang liver cell assessed using MTT assay method indicated that both plant extracts which were inhibitory to the proliferation of cell lines with IC50> 20 μg/mL appear to be safe. This report provides the first evidence of in vitro schistosomicidal potency ofR. vomitoriawith the stem bark being moderately, but relatively, more active and selective against schistosome parasites. This suggests the presence of promising medicinal constituent(s).


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