Exhibit label

Xandiene dyes have not exhibited health or safety properties warranting special precautions however, standard chemical labeling instmctions are required. Toxicological properties of important dyes are Hsted in Table 2 (12). 

The mode of action has not yet been elucidated but the manufacturer states that it probably behaves like the herbicide triflurolin and its congeners. These materials inhibit cell division by binding to tubuHn thereby internipting micro-tubule development. This, in turn, stops spindle fiber formation essential to mitosis and cell division. Experiments with C-labeled Prime+ show that it is acutely toxic to fish with estimated LC q (96 h) of less than 100 ppb for rainbow trout and bluegiU. sunfish. However, channel catfish did not exhibit any toxic response at the maximum attainable water concentration (10). 

The growth rate for tracers labeled with short-Hved isotopes such as P and was about 10—15% per year from 1990 through 1994. This trend reflects the increased use of these radiochemicals for research in molecular biology and genetics I-labeled tracers have also exhibited similar growth rates in this period. On the other hand, the market for C- and H-labeled chemicals essentiaHy leveled off The overaH growth rate for aH tracer chemicals was estimated at 5%/yr for 1990—1994. 

General trends in radiopharmaceutical research emphasize the use of small peptides. These molecules, of which the agents mentioned for thrombosis localization are an example, exhibit rapid and specific binding, and rapid blood clearance, two important parameters for a successflil radiopharmaceutical. Peptides are readily labeled with Tc and lend themselves to formulation as lyophilized kits that can be rapidly and rehably reconstituted. Possible targets for these molecules are quite varied, ranging from atherosclerotic plaque to P-amyloid (for Alzheimer s disease), to a variety of somatic receptors the populations of which are increased or decreased in disease. 

When the l<, 2( -d2-labeled product (129) is subjected to alkaline equilibration to back exchange the 2i -label (for experimental conditions see section IT-B), the crystalline l< -di-4,4-dimethyl-5a-androstan-3-one (130) exhibits 6% do and 94% d isotopic composition. ... 

During the course of a mass spectrometric study of D-homo-14-hydroxy steroids, it was necessary to prepare the corresponding C-8 deuterium labeled analogs. The preparation of these uncommon steroid derivatives has been achieved by repeating the Torgov total synthesis [(257) (262)] with a deuterium-labeled bicyclic starting material (258). Both of the resulting 14-hydroxy epimers, (261) and (262), exhibited better than 90% isotopic purity. ... 

In contrast to PEG-1000, the ESR-spectra obtained for labelled grafted PEO-oligomers (N = 1-9) were reported to differ strongly from that for N = 23 and exhibited only slowly moving labels. As the fine width of the fast domain spectrum depends on the mobility of the label, it can be concluded that the tails for N = 23 must consist of at least 4-9 repeated units. It appears that some tails are rather long. 

Complexed arenediazonium salts are stabilized against photochemical degradation (Bartsch et al., 1977). This effect was studied in the former German Democratic Republic in the context of research and development work on diazo copying processes (Israel, 1982 Becker et al., 1984) as well as in China (Liu et al., 1989). The comparison of diazonium ion complexation by 18-crown-6 and dibenzo-18-crown-6 is most interesting. Becker at al. (1984) found mainly the products of heterolytic dediazoniation when 18-crown-6 was present in photolyses with a medium pressure mercury lamp, but products of homolysis appeared in the presence of dibenzo-18-crown-6. The dibenzo host complex exhibited a charge-transfer absorption on the bathochromic slope of the diazonio band. Results on the photo-CIDNP effect in the 15N NMR spectra of isotopically labeled diazonium salts complexed by dibenzo-18-crown-6 indicate that the primary step is a single electron transfer. 

Further experiments with labeled precursors were necessary to shed a little more light on this puzzling observation. Pyramine, biosynthesized from AIRs labeled with, 4C on C-l on the ribose part, exhibited only marginal radioactivity. This result rules out C-l of ribose in AIRs as a precursor of pyramine. This conclusion was confirmed with a precursor labeled at the C-l position with the stable l3C isotope. The mass spectrum of the ethylthio derivative of pyramine was identical with that of an unlabeled sample (Scheme 9). 

Figure 1. Immunofluorescent labeling of dystrophin in the Xp21 muscular dystrophies. In normal muscle, clear uniform labeling is present at the membrane of each muscle fiber. In Becker muscular dystrophy (BMD), there is inter- and intrafiber variation in labeling intensity. In Duchenne muscular dystrophy (DMD), most fibers are devoid of labeling (note, however, that in most biopsies occasional fibers exhibit weak labeling). In the biopsy from a manifesting carrier, some fibers show normal labeling and others are negative. In the former, the normal X-chromosome is active while in the latter the abnormal X-chromosome is active.

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