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Radio-labeled study results

Recently, it has been shown that cell-permeable cerantides dramatically inhibited the synthesis of the two major membrane phospholipids, PC and PE (Bladergroen et al, 1999b Allan, 2000). The inhibition of phospholipid synthesis was rapid, within 2 h, and resulted in massive apoptosis after 16-24 h. The mechanism by which short-chain cerantides exert their effect on phospholipid synthesis is possibly cell type dependent. In baby-hamster kidney (BHK) fibroblasts rc synthesis was reduced at the level of CT, the putative rate-determining enzyme in the CDP-choline pathway (Allan, 2000). This conclusion was based solely on radio-label studies in combination with an earlier published observation (Wieder et al, 1995) showing that C2-SM (the SM generated from C2-ceramide by SM synthase, which was actively synthesized in the BHK-cells) inhibited CT activity in vitro. On the other hand, data obtained from studies with rat-2 fibroblasts clearly showed that short-chain cerantides regulate the synthesis of PC and PE mainly at the final step of the CDP-pathways. This conclusion was based on the following observations (a) incorporation of [ H]-choline into PC and... [Pg.212]

The results on the hydrolysis of partially methylated /3-casein by plasmin indicate that proteins radiomethylated to a low level can serve as substrates for trypsin-like enzymes and probably for proteinases in general. Because it is likely that methylation will interfere with enzymatic attack at lysine residues, the complete hydrolysis of /3-casein probably would not be possible. Studies on mastitic milk demonstrate the usefulness of 14C-methyl proteins for qualitative examination of protein hydrolysis in complex multiprotein systems where resolution and characterization of individual protein fragments is difficult. The requirements in such studies are the availability of pure samples of the proteins under investigation and a suitable technique for separating the radio-labeled protein from hydrolytic products. [Pg.148]

The residue levels of PBO and HMDS for the assayed commodities are presented in Table 10.3. The results show that the highest residues of both PBO and HMDS were found on leafy crops (e.g. lettuce, mustard greens, etc.) which are directly exposed to the spray. Lower residues are found on fruits and less exposed stems (e.g. broccoli) and minimal residues are found in commodities which are not directly exposed (e.g. potato tubers). Little or no translocation of PBO or closely related metabolites occurred. Low residue levels of HMDS-producing metabolites were found away from tbe application site. The results confirm the findings of the radio label led metabolism studies. [Pg.168]

Towards this end, studies were carried out which included the radio-labelling of the somatostatin receptor ligand DOTA-Tyr -TATE (1,4,7,10-tetraazacyclotetradecane-N,N, N",N" -tetraacetic acid tyrosineS-octreotate, or DOTATATE) with both Lu and I, and the quality control of the resulting complexes. In vitro studies of the biological affinity of the Lu-DOTATATE and I-DOTATATE for the somatostatin membrane receptor were carried out with the help of competition and saturation binding assays. In vivo studies of the biodistribution of Lu-DOTATATE and I-DOTATA TL in animals, either alone or in competition, were also carried out. The radiotherapeutic effect of "Lu-DOTATATE was evaluated by cytometry measurements. Estimation of absorbed doses of Lu-DOTATATE was carried out by mathematical modelling. [Pg.234]

It is possible that the lower than required values of D2 reflect a problem with incorrect values of Q, which if too large would result in smaller values of D2. In an interferometric study of the diffusion of toluene in an uncrosslinked natural rubber sample, Mozisek (15) reported results for the mutual diffusion coefficient which were similar to the results of Hayes and Park. In the absence of thermodynamic data from Mozisek s work, correction factors calculated for the present work were applied to his data. The results are shown in Figure 7, which reproduces Mozisek s data along with the values for D2. The extrapolated value at 1, would exceed the self diffusion coefficient for toluene by about two orders of magnitude, similar to the discrepancy seen with Hayes and Park s data. This indicates that the fault with the results in the present case is not due to overly high values of the correction factors. Moreover, the method of calculating D from D12 has been confirmed experimentally by Duda and Vrentas (16) in a comparison of vapor sorption results for toluene diffusion in molten polystyrene with the values of D1 obtained directly using radio-labeled toluene. [Pg.387]

Particularly in the cases of snRNAs, tRNAs, and rRNAs, in vitro transcripts will lack covalent base and/or sugar modifications found on native cellular (RNAs (Taylor era/. 1971 Reddy and Busch, 1988 Patton, 1994 Lane etai, 1995 Maden et al., 1995). Although these modifications usually occur to in vitro transcripts over time within injected oocytes, it is sometimes desirable to study the nuclear transport of P-labeled native RNAs. For these experiments, radio-labeled RNAs are prepared by metabolic labeling of transcripts produced from endogenous genes or from genes that are microinjected, usually as plasmid DNA, into oocyte nuclei. The resultant RNAs are purified and injected into oocytes as described above. [Pg.567]

Biocompatibility studies of PROZOs using a radio-labeled polymer found that when PMeOZO and PEtOZO were administrated in mice, they were excreted without accumulation from the bloodstream. These results suggest that the polymers possess the stealth nature, meaning the suppression of all interactions with the body, being free from the immune system. This is beneficial for application as drug carriers and other biomedical purposes. [Pg.422]

Although the number of studies using (radio) labeled substrates in an attempt to confirm the generation of these PIAs in nature is limited, numerous biosynthetic hypotheses occupy the chemical/synthetic literature [34, 35]. These proposals represent all levels of the complexity spectrum for this family, from simple cyclic compounds derived from an oroidin monomer to those that result from dimerization of oroidin and further cyclizations. To prevent this chapter from occupying the whole book, only two examples will be presented in this subsection to serve as a general overview. [Pg.477]


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Labeling study

Labelling studies

RADIO LABELLING

Radio labeled

Radio, radios

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