Tissue model

Cystic fibrosis (CF) is caused by mutations in the CF transmembrane conductance regulator (CFTR), a chloride (CF) channel characterised by chloride permeability and secretion, and also by the regulation of other epithelial ion channels (Eidelman et al, 2001). Mutations in the CFTR gene lead to an impaired or absent Cl conductance in the epithelial apical membrane, which leads to defective Cl secretion and absorption across the epithelium. Genistein (Illek et al, 1995 Weinreich et al, 1997) and other flavonoids (Illek and Fisher, 1998) have been shown, in different animal and tissue models, to activate wild-type CFTR and CFTR mutants by (Eidelman et al, 2001 Roomans, 2001 Suaud et al, 2002) ... 

The mass transfer coefficients may also be expressed in units of time-1 by multiplying by the appropriate compartmental volume term. Irreversible drug elimination from the tissue requires the addition of an expression to the differential equation that represents the subcompartment in which elimination occurs. For instance, hepatic drug elimination would be described by a linear or nonlinear expression added to the intracellular liver compartment mass balance equation since this compartment represents the hepatocytes. Formal elimination terms are given below for the simplified tissue models. 

The three-compartment tissue model is ordinarily simplified by lumping all three subcompartments, lumping subcompartments 1 and 2, or lumping subcompartments 2 and 3. These simplifications result in the blood flow-limited (i.e., lumping all three subcompartments) and the membrane-limited (i.e., lumping any two subcompartments) tissue models. Differential mass balance equations for a noneliminating membrane-limited compartment are... 

MacGregor JT et al. In vitro tissue models in risk assessment report of a consensus-building workshop. Toxicol Sci 2001 59 17-36. 

To test further this hypothesis, a simulated cell/tissue model system has been devised using quantitatively comparable cell fines, in which the amount of selected antigen (potential reference standard) can be measured accurately on a cell-to-cell basis in fresh and FFPE specimens that are processed under clearly defined but variable conditions, including periods of formalin fixation, delay times of fixation (prefixation time or warm ischemic time), storage conditions, and other technical issues such as thickness of each tissue section, in... 

Instruments). The antibody panel will be selected to include ubiquitous cytoplasmic, nuclear, and surface markers. Accurate biochemical quantification of proteins in the cell/tissue model will be undertaken for validation of the IHC findings. 

A research design using the cell/tissue model is presented to encourage examination of the limitations of this hypothesis, based on correlation of accurate quantitative biochemical measurements and precisely measured IHC staining results. 

Establish a cell/tissue model that is reproducible Western blot or mass spec for 6-10 different proteins present, at range of concentrations from low to high. 

The use of independent methods, other than IFIC, for quantitative demonstration of proteins is particularly important. Both enzyme-linked immunosorbent assay (ELISA) and Western blot may be employed to confirm the amount of protein in a cell/tissue model, and in the protein-embedding bar code model under both comparable fresh and FFPE samples for accurate... 

Variables for normal tissue models in ventricular tissue. Also has type II,/3-blocking actions. 

Kubilus J, Ayehunie S, Breyfogle B, Dale DA, Kimball J, Wertz P, Klausner M (2006) Characterization and testing of new buccal and gingival tissue models. American Association of Dental Res. Meeting 399. 

Ethical issues as well as difficulty in obtaining enough human nasal tissue specimens have called for the need to use alternative in vitro and in vivo methods. Various in vivo animal models and in vitro excised tissue models have been described in the literature for nasal drug transport studies. However, due to the difficulty in both controlling the experimental conditions in in vivo animal models and obtaining intact excised tissue samples, in vitro cell culture models are also being actively developed. 

Excised nasal mucosae obtained from various animal species are tools frequently used to study nasal transport and metabolism ([53], Chap. 4). Maintaining the viability of the excised nasal tissues during the experimental period is crucial. Most studies were performed with epithelia excised from rabbits, bovine, sheep, and dogs tissues [54-57], This excised nasal tissue model has been shown to be well suited for studies on nasal permeation and metabolism of drugs. However, species differences in the activity of various enzymes found in human versus these animal nasal mucosae have become an important issue. 

Birchall, J. C., et al.. Gene expression in an intact ex-vivo skin tissue model following percutaneous delivery of cationic liposome-plasmid DNA complexes. Int. J. Pharm., 197, 233-38, 2000. 

The EpiDerm (EPI-200) skin model is mechanistically and functionally related to EPISKIN. The assay consists of normal human epidermal keratinocytes, which have been cultured in a chemically defined medium to produce a stratified, highly diEerentiated, organotypic tissue model of the human epidermis. 

Mastro AM, Vogler EA (2009) A three-dimensional osteogenic tissue model for the study of metastatic tumor cell interactions with bone. Cancer Res 69 4097 100... 

Prestwich GD, liu Y, Yu B et al (2007) 3-D culture in synthetic extracellular matrices new tissue models for drug toxicology and cancer drug discovery. Adv Enzyme Regul 47 196-207... 

SRI evaluates drug metabolism and drug interactions, using human and animal (rat, dog, and monkey) tissue models based on human hepatocytes. It also extends services for the metabolite profiling of drug candidates using hepa-... 

In vitro and ex vivo intestinal tissue models to measure mucoadhesion of poly (methacrylate) and N-trimethylated chitosan polymers. Pharmaceutical Research, 22, 38-49. 

Lammertsma, A.A., Hume, S.P. Simplified reference tissue model for PET receptor studies. Neuroimage 4, 153-158, 1996. 

Figure 15-5. a) Schematic structure of solid Na20-Si02, crystal and glass. Si4+ Al3+ O 02 Na+. b) Cluster tissue model of glass. areas of increased stresses. 

Overall, the results obtained for the last two families suggest that the geometry of cationic lipid plays an important role in the final structure of the bilayers and thus affects the transfection efficiency. Nevertheless, this geometric effect seems to differ for different tissue models. 

This study reports on the potentiality of applying a membrane biohybrid system in the field of tissue engineering and regenerative medicine evidencing the crucial points in the in-vitro reconstruction of the physiological tissue model. A number of issues need to be addressed the morphological and physicochemical properties of the membrane, the optimal density of immobilized cells, the interaction of cells with the membrane, the differentiation of cells as well as the maintenance of viability and... 

Lin X, Paskaleva EE, Chang W et al (2011) Inhibition of HIV-1 infection in ex vivo cervical tissue model of human vagina by palmitic acid implications for a microbicide development. PLoS One 6 e24803... 

Physiologically based pharmacokinetic (PBPK) models are used to estimate the dose of toxic metabolites reaching target tissues. Model outputs provide internal dose estimates for specific life stages and differences between sexes, species, dose routes, and exposure patterns. These models provide a tool for understanding the... 

---