Labeling of specimen

Properties (1) and (2), combined with the fact that quantum dot emission spectra are characteristically narrow and symmetrical compared to those of conventional fluorochromes, offer considerable potential for clean, multiple fluorescence labeling of specimens. With appropriate emission filters in place, the same excitation wavelengths can be used to produce fluorescence from carefully selected quantum dots of different sizes, resulting in the emission of closely spaced, but nonoverlapping colors. 

Fig. 3. Head of a Hydra oligactis labeled with monoclonal antibody DBS. (A) Neurons of hypostome and perihypostomal ring (left) and base of tentacle (right) at high magnification (x 20 objective) note considerable out-of-focus labeling of the tentacle (B) same specimen as in (A) but at lower magnification (x 10 objective) although the hypostome is out of focus, the neuronal net of the tentacles is much clearer. Scale bars = 50 pm.

When fluorescently labeled biological specimens are viewed with a conventional wide-field microscope, a haze of out-of-focus fluorescence is usually created hy the overlapping structures within the sample. As we focus through the specimen, our hrains have a remarkable ability to discern substantial structural detail. However, the resolution of the images we record on film is degraded hy the out-of-focus fluorescence. The confocal microscope can reject out-of-focus information and enhance the contrast of an image because the illumination and the detection are confined to an identical (small) region of the specimen. An overview of the basic principles of a confocal microscope is presented in Fig. 1 and outlined helow. 

Controls with the anti-glycohydrolases IgG, first incubated with the enzymic extract before being applied in thin sections, showed no labeling (Fig. 2B). Other controls performed, i.e., replacement of the primary antibody by normal rabbit serum or preimmune serum, suppression of the first step corresponding to the primary antibody, or labeling of uninfected wood specimen, were also negative. 

The proper identification of specimens is of obvious importance to the validity of a study. Because of the size or nature of the material, some types of specimens (e.g., paraffin blocks and microscopic slides) do not lend themselves to labeling for all the items listed in 58.130(c). In such cases the use of an alternative identification (e.g., accession numbers) is acceptable as long as the alternate identification can be translated into the required information. 

Precursors such as reticuline 10 were synthesized labelled with 14C (O and N methyl groups) and with 3H in the aromatic nuclei. Labelling could also be done in the two 2-carbon bridges. We also synthesized from thebaine the key alkaloid 11 for the first time. Unlike the situation with Pummerer s ketone 11 did not close to 12 spontaneously. Later on, alkaloid 11 was isolated from a Brazilian plant. From correspondence with Prof. R. A. Barnes, we realized that the two were probably identical, which was confirmed by an exchange of specimens. So, we used thereafter the name salutaridine, given by our Brazilian colleagues. 

In the case of metal dissolution studies the principle of the methods used is based on the labeling of a component of the metal phase by one of its radioactive isotopes and calculating the dissolution rate of the metal specimen by measuring either the increase in radiation coming from the solution phase, or the decrease in radiation coming from the solid phase. 

The specimens should be collected by qualified personnel and each container into which a specimen is placed must bear a label with the name of the subject, the type of specimen in the container, the date and time of the collection of the specimens, and the signature of the person collecting the specimen. Forms and labels are usually developed to facilitate inventory of the specimens collected and to document the activities at the collection site. Frequently, a police officer is at the scene of the collection of the specimen and that officer should also append his or her signature to the labels and form. The specimens collected should be properly packaged with the proper documentation and case history if available and transferred to a forensic laboratory for analysis. 

The first action is to make groups of specimens according to their overall resemblance. Look at each specimen and make piles of the plants which look the same. While doing this do not look at the names on the labels, because names may be wrong I... 

A major advance in the automation of specimen identification in the clinical laboratory has been the incorporation of bar coding technology into analytical systems.In practice, a bar coded label (often generated by the laboratory information system and bearing the specimen accession number) is placed onto the specimen container and is subsequently read by one or more bar code readers that have been strategically placed at key positions in the analytical train. The resultant identifying and ancillary information is then transferred to and processed by the system software. 

---