Organ Slices

Plasma and urine samples were profiled using a suitable HPLC system under specific conditions (gradient, column). Readout was done off-line by fraction collection of the HPLC ran followed by liquid scintillation counting. Biotransformation profiles were prepared by plotting the base-line corrected radioactivity against time-after-injection. 

For metabolite isolation, 1.5 liters of pooled urine were applied to a XAD-2 resin column first. The ethyl acetate extract obtained containing 85 % of the radioactivity was applied upon evaporation to semipreparative HPLC on a Zorbax RX C18 column (9.4 x 250 mm, 5 pm) using gradient elution. Fractions obtained were further separated by isocratic elution on the semipreparative column. The metabolite fractions obtained were finally purified by preparative thin-layer chromatography. Liquid chromatography/mass spectrometry (LC/MS) and LC/MS/MS analysis was applied to the isolated metabolite fractions for structure elucidation. 

Concentration of the drug and related metabolites are determined using appropriate analytical methods such as HPLC, LC-MS or LC-MS/MS techniques. The 

Enser MB, Kunz F, Borensztajn J et al. (1967) Metabolism of triglyceride fatty acid by the perfused rat heart. Biochem J 104 306-317 

Kaneda Y, Liu D, Brooks A et al. (2001) Toxicity and pharmacokinetics of isolated lung perfusion with cisplatin in rat. Jpn J Thorac Cardiovasc Surg 49 443-448 Newton JFJ, Hook JB (1981) Isolated perfused rat kidney. Methods Enzymol 77 94-105 

---

Chick embryo neural retina cells have also been grown in culture (Daston et al., 1995), and studies indicate positive responses to chemicals at concentrations similar to those active in in vivo tests. Reinhardt (1993) has reviewed the use of organ slices, aggregate cell cultures and the micromass techniques for the study of neurodev-elopmental toxicity. Two recent reviews of these in vitro systems, especially the micromass and the chick embryo neural retinal cell system, have been published (Daston, 1996a Mirkes, 1996). 

Organ slices are applicable to long-term cultures, viability up to 72 h has been described for rat liver slices (Fisher 1995). On the other and, investigation of enzyme activity revealed changes in the metabolic capacity of phase I and phase II enzymes in long-term cultures (Vandenbranden 1998). De Kanter (1995) established a general method for cryopreservation of slices. The best viability of rat liver slices was found by exposure for 30 minutes to 12 % dimethyl sulfoxide... 

Vickers AE, Saulnier M, Cruz E, Merema MT, Rose K, Bentley P, Olinga P (2004) Organ slice viability extended for pathway characterization an in vitro model to investigate fibrosis. Toxicol Sci 82(2) 534-544... 

The activity of histidine decarboxylase preparations can be measured by determining either of the decarboxylation products of histidine, i.e. histamine or carbon dioxide. Most of the methods are in vitro techniques using organ slices, minces or cell-free extracts, and they have the usual limitations of in vitro measurements - - . In vivo methods have also been used, but these give information primarily about the decarboxylation of histidine in the body as a whole rather than about the distribution of the enzyme in specific organs. 

Discussion. Labeling experiments in which a number of C labeled acids were administrated to barley organ slices gave B-diketones containing the isotopic marker. Diketones were isolated and degradated by basic hydrolysis to fatty acids whose radioactivity was measured. Some data most pertinent to our discussion are reported in the Table. 

Further subdivision of a five-digit slice utilizes lower-case Roman numerals in parentheses (i), (ii), (iii), etc. It is often found that as a consequence of the organization, cognate material is located in different chapters but in similarly numbered pieces, i.e., in parallel sections. Section numbers, rather than page numbers, are the key by which the material is accessed through the various indexes. 

ATP certainly fulfils the criteria for a NT. It is mostly synthesised by mitochondrial oxidative phosphorylation using glucose taken up by the nerve terminal. Much of that ATP is, of course, required to help maintain Na+/K+ ATPase activity and the resting membrane potential as well as a Ca +ATPase, protein kinases and the vesicular binding and release of various NTs. But that leaves some for release as a NT. This has been shown in many peripheral tissues and organs with sympathetic and parasympathetic innervation as well as in brain slices, synaptosomes and from in vivo studies with microdialysis and the cortical cup. There is also evidence that in sympathetically innervated tissue some extracellular ATP originates from the activated postsynaptic cell. While most of the released ATP comes from vesicles containing other NTs, some... 

R. Kuchenbuch and A. Jungk, A method for determining concentration profiles at the soil root interface by thin slicing rhizosphere. soil. Plant Soil 68 39 (1982). D. Zabowski, Limited release of soluble organics from roots during the centrifugal extraction of soil solutions. Soil Sci. Soc. Am. J. 53 911 (1989). 

Studies on in vitro systems of various kinds (including whole perfused organs, tissue slices, cell, tissue and organotypic cultures, and sub cellular fractions). 

Flowever, the object being analyzed has to be removed from the tissues. Thus, information about the distribution of the target in the organism or in the cells is inevitably lost. What is now needed is a technology to acquire information about the distribution of the biomolecule simultaneously with its identification. The method used for this purpose, called imaging mass spectrometry (IMS), is as follows. The tissue sample is cut into thin slices, and a matrix that assists the ionization of macromolecules is spread onto these slices. The macromolecules are then ionized by a scanning laser, and the generated ions are detected and analyzed by MS.1... 

Because disrupted tissue preparations were unsatisfactory, attempts were made to work either with more organized systems such as tissue slices (liver-Krebs) or to identify and isolate the intracellular organelles involved in the reactions. Cytochemical procedures were developed in the 1930s and 1940s to locate sites of reaction in situ in cells (Chapter 9). Examination of cell ultrastructure became possible when the electron microscope was introduced after 1945. Techniques for the isolation of cell organelles, notably mitochondria, were developed about this time (Chapter 9). 

In vitro studies in our laboratory involving 1-h incubations of 0.5-g liver slices of rainbow trout with 10 ml of 1-, 2.5, and 5-mg/100 ml concentrations of MS-222, resulted in 8.5, 6.9, and k.2% (respectively) of the drug being acetylated. Similar incubations of kidney tissue resulted in 0, 0, and 3.2% acetylation. These incubation studies indicate that the liver is the prime site of acetylation of MS-222, but suggest that some may occur in the kidney as well. However, in vitro evaluation of the acetylating capability of rainbow trout kidney is complicated by the diffuse structure and heavy pigmentation of the organ. 

Pyroelectric detectors depend on the use of a thin slice of ferroelectric material (deuterated triglycine sulfate [DTGS], Figure 5.6, is the standard example) - in which the molecules of the organic crystal are naturally aligned with a permanent electric dipole. The thin slab is cut and arranged such that the direction... 

---