Explant test

Koschwanez HE, Reichert WM. In vitro, in vivo and post explantation testing of glucosedetecting biosensors current methods and recommendations. Biomaterials 2007, 28, 3687-3703. 

Human placental Placental chorionic vllloua development explants test t... 

Torzilli, P. A., R. Grigiene, C. Huang et aL 1997. Characterization of cartilage metabolic response to static and dynamic stress using a mechanical explant test system. Biomech 30 1-9. 

Observation of effects. Seven to 14 days after exposure to test compounds, length, number of leaves and presence of stomata in sprouted winterbuds were determined. FOr sago pondweed tubers, length, number of new daughter plants and presence of roots were determined. Hydrilla explants were evaluated for number of and length of new shoots. In some experiments the chlorophyll-a content of the apical 2 cm on apical explants was determined by 3 successive extractions in 90% acetone using a power-driven Teflon pestle. Absorbance of Millipore-filtered (.45p ) acetone extracts was determined at 6 30, 6 45, 6 6 5 nm on a spectrophotometer. Chlorophyll-a was calculated by equations of Strickland and Parsons (8). 

Bioassays. Four bioassays were developed to test the phytotoxic affect of spikerush leachate. Two assays involving target plants (hydrilla and sago pondweed) were tested at the explant level. Two additional assays were developed, one involving whole plants... 

Nonpolar extracts were not tested in either the hydrilla explant or the sago shoot assay due to the limited supply of material. 

B[/ ]P metabolites have been shown to bind to DNA in culmred human hepatocytes and in human bladder and tracheobronchial explants. The metabolites identified were identical to those produced in other species and differed only in the relative percentages of formation. Human tissues were most active in metabolizing P>[a P and exhibited at least a threefold higher covalent binding of metabolites to DNA than hamsters, dogs, monkeys, or rats. In addition, P>[a P has been tested extensively in several bacterial and mammalian cell systems and has been chosen as a positive control for the validation of some of these systems. ... 

Sprague-Dawley rats exposed to toluene (982 52 ppm [3700 196 mg/m ], 18 h per day, on seven days per week for 61 days) showed no evidence of histological damage to the testes two weeks or 10 months after cessation of the exposure (Nylen et al., 1989). Toluene (the concentration of which decreased during the incubations) did not induce malformations in explanted rat embryos at the highest concentrations tested (0.23-0.09 mg/L), but retarded the growth of the embryos at the lowest concentration tested (0.05-0.02 mg/L) (Brown-Woodman et al., 1991). 

Roles of Metabolites of Abscisic Acid. Nothing is known about the physiological role of PA and DPA in plants, although these two metabolites of ABA have been tested in several bioassays recently. In the cotton explant abscission assay PA had one-tenth of the activity of ABA (19). PA and DPA were equally effective in inhibiting a-amylase secretion by barley aleurone layers treated with glbberellin A3 DPA had approximately one-tenth of the activity of ABA in this system (74). The effect of PA on growth of bean embryos was negligible (75). 

Steinmeyer J (1997) A computer-controlled mechanical culture system for biological testing of articular cartilage explants. J Biomechanics 30 841-845... 

Correction of the chloride channel defect in cells explanted from CF patients by the introduction of the normal CFTR cDNA suggests that gene therapy may be beneficial. It may be sufficient to deliver the normal cDNA just to the respiratory epithelial cells. A number of strategies for gene therapy by using viral vectors and other delivery methods are under development and are being tested (Collins, 1992). These approaches are discussed in detail in Chapter 6. 

There are a number of fully in vitro screens as well, employing mammalian, lower vertebrate, and invertebrate species. Materials used include explanted rat or mouse embryos cultured in rodent serum to which is added the test agent or known metabolites, and... 

Explanted chick embryos at presomite or multiple somite stages or chick embryonic parts are cultured with the test agent incorporated into the culture medium and evaluated for growth and differentiation. 

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