-derived products identifiable in the systemic circulation, bacterial endotoxin [i.e., lipopolysaccharide (LPS)], and gut metabolites [e.g., p-cresyl sulfate and trimethylamine-N-oxide (TMAO)] have been extensively studied for their immunostimulatory and atherogenic
The quality tests of radionuclides produced from generators (99Mo→99mTc,113Sn→113mIn) have been reviewed. The quality controls of radiopharmaceuticals derived from these radionuclides and prepared with the
help of ready-for-use reagents assembled in kits have been presented. The possibility of new tests regarding sterility (by
means of a radiometric method) and detection of endotoxin (based on gelification of limulus amoebocyte lysate) have been suggested.
We used artificial planar lipid membranes to investigate, the mode of action of cytolysins of different origin. We studied some pathologically important bacterial toxins (e. g. S. aureus -toxin, C. perfringens -toxin, B. thuringiensis -endotoxin and E. coli -hemolysin). All these toxins are used by the bacteria to damage the cells of the invaded organism. We also studied cytolysins of animal origin which are used to react against the attack of foreign organisms like cytolysins from the nematocysts of sea anemones. These proteins disrupt the permeability barrier of the attacked cell membrane by opening a pore into the lipid matrix. We found that in most cases a receptor is not truly required to render them competent to bind to a cell membrane, they spontaneously insert into preformed pure lipid membranes. Several properties of the resulting pores were compared. They are generally large, water filled, and stay open for long periods. In most cases neutral molecules up to a few kDa molecular weight (like sugars and metabolites) can easily pass through the channel. They are weakly selective, usually being able to discriminate only between anions and cations. The selectivity depends on the presence of fixed charges on the protein since it is modulated by pH and by chemical modification of the protein charged residues.
[18F]-3′-deoxy-3′-fluorothymidine ([18F]FLT) is an established positron emission tomograph (PET)—radiopharmaceutical to study cell-proliferation rate in tumors.
Very low practical yield, uncertain and time-consuming high performance liquid chromatography (HPLC) purification, are the
main obstacles for the routine use of [18F]FLT in clinical PET. To obviate these difficulties, we have developed a fully automated radiosynthesis procedure for [18F]FLT using 5′-O-(4,4′-dimethoxytriphenylmethyl)-2,3′-anhydro-thymidine (DMTThy) and simplified single neutral alumina column purification.
The [18F]FLT yield was 8.48 ± 0.93% (n = 5) (without radioactive decay correction) in a synthesis time of 68 ± 3 min. The radiochemical purity was greater than
95% as confirmed by analytical HPLC using reference standard FLT and also free of non-radioactive impurity. Soluble aluminum
in the final product was much below the permissible limits. Di-methyl sulfoxide (DMSO), the reaction medium, could be detected
in the final product in trace amounts, well below the permissible levels. The synthesized [18F]FLT was sterile and bacterial endotoxin free by appropriate tests. PET imaging study in normal rabbits showed distinct localization
of [18F]FLT in organs having rapid cell division rate like bone marrow, guts and snout and the excretion was through the renal route.
There were no significant uptakes in bone and brain. The former finding confirms the in vivo stability of the [18F]FLT. This simplified radiosynthesis procedure can easily be adapted in any commercial or indigenous [18F]FDG synthesis module for routine [18F]FLT synthesis without the need of additional automation for HPLC purification.
treatment that the bacteria have undergone during production.
Bacterial LPS, also known as endotoxin, has been described in association with a number of diseases, including liver damage [ 1 ], neurological degeneration (Parkinson's disease and
Authors:Á. Szepesszentgyörgyi, S. Bárány, and I. Mécs
Kuppusamy, M., Balaraman, K. (1991) Fed-batch fermentation studies with Bacillus thuringiensis H-14 synthesising endotoxin. Indian J. Exp. Biol. 29, 1031-1034.
Fed-batch fermentation studies with Bacillus thuringiensis H-14