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Multidrug resistance conferring proteins (MDRCP) are ATP-binding cassette (ABC) transporters known to significantly influence the absorption, distribution, metabolism, and elimination (ADME) and toxic behavior of many therapeutic agents. Research in the pharmacogenomics area has suggested that mutations and variable expression patterns of these MDCRPs may exist in tissue samples from different ethnic groups. The goal of this study was to examine the expression of P-glycoprotein (PGP), sister of PGP (S-PGP), multidrug resistance protein 3 (Mdr3), multidrug resistance like proteins 1−5 (MRP 1−5), and lung resistance associated protein (LRP) in tissue slides and protein lysates derived from normal adult small or large intestines of Caucasian or Chinese origin. Our results demonstrated ubiquitous expression of PGP, MRP 1, MRP 4, and LRP in the small and large intestinal epitheliums originating from both Caucasian and Chinese origin. S-PGP, Mdr3, MRP 2, and MRP 3 exhibited variable expression in the tissue slides and protein lysates derived from the Chinese and Caucasian small and large intestines. MRP 5 was not observed in any of the samples studied. The results suggest that MDCRPs may have distinct expression profiles in the small and large intestines that potentially vary with genetic background. These studies provide a foundation for further investigations to verify these findings across a wider number of patients of different ethnic backgrounds. Keywords: Multidrug resistance; LRP; MRP; Mdr; P-glycoprotein

Stably transfected MDCK/hPepT1-V5&His clonal cell lines expressing varying levels of epitope-tagged hPepT1 protein were established to quantify the relationship between transgene hPepT1 expression levels and its functional kinetics in facilitating peptide and peptide-like drug uptake and transport in vitro. The hPepT1 sequence was amplified from Caco-2 cell mRNA, inserted into the pcDNA3.1-V5&His TOPO plasmid, and transfected into MDCK cells. Transgene protein levels were quantified by Western Blot analysis utilizing a standard curve generated with a positive control protein containing a V5&His epitope. Three clones expressing different levels of the hPepT1 fusion protein (low, medium, and high) were selected for the functional characterization with [¹⁴C]Gly-Sar and [³H]carnosine. The MDCK/hPepT1 cells expressed a novel hPepT1/epitope tag protein with an apparent molecular mass of 110 kDa. The [¹⁴C]Gly-Sar uptake in the transfected cells was sodium-independent and pH-dependent, demonstrating enhanced uptake, the rate of which increased significantly from the weakly to strongly expressing hPepT1 MDCK/hPepT1-V5&His clones as compared to the mock cell line at pH 6.0. The uptake and permeability of [¹⁴C]Gly-Sar and [³H]carnosine demonstrated a direct correlation between the hPepT1 level of expression, uptake, and transport capabilities. Molecular and functional characterization of the MDCK/hPepT1-V5&His cell line confirmed a directly proportional relationship between Vmax and Papp versus the molar levels of hPepT1 transgene expression. This stably transfected hPepT1 cell line may serve as a useful in vitro model for screening and quantifying peptide and peptide-like drug transport as a function of hPepT1 expression in drug discovery. Keywords: Human peptide transporter 1; glycylsarcosine; reverse transcriptase polymerase chain reaction; apparent permeability

Excess molar volumes %@mt;sys@%%@ital@%V%@rsf@%%@mh;1q@%%@sx@%m%@be@%E%@sxx@%%@mx@% and viscosities η have been measured as a function of composition for binary mixtures of 2-propoxyethanol and of 2-isopropoxyethanol with 2-pyrrolidinone, N-methyl-2-pyrrolidinone, N,N-dimethylformamide, and N,N-dimethylacetamide at 298.15 K. In all mixtures, the excess molar volumes are negative over the whole mole fraction range. From the experimental data, deviations in the viscosity Δ ln η had been calculated. The excess volumes and viscosity deviations have been correlated using the Redlich−Kister polynomial equation by the method of least-squares for the estimation of the adjustable parameters and the standard errors. The viscosity data have been correlated with the equations of McAllister, Heric, and Auslaender.

Excess molar volumes %@mt;sys@%%@ital@%V%@rsf@%%@sx@%m%@be@%E%@sxx@%%@mx@% and viscosities η have been measured as a function of composition for the binary mixtures of 2-propoxyethanol and of 2-isopropoxyethanol with propylamine and dipropylamine at (298.15, 308.15, and 318.15) K. From the experimental data, the deviation in the viscosity η from ∑xi ln ηi has been calculated at various temperatures. The excess molar volumes are negative whereas the deviation in the viscosities is positive for all investigated systems over the whole composition range. These results suggest that the stronger hydrogen bonds between unlike molecules reduce the volume of the solution and make the solution high viscosity. A Redlich−Kister type equation was applied to fit the excess volumes and viscosity deviations, and McAllister's three-body and four-body interaction models were also used to correlate the kinematic viscosities.

Prediction of heat transfer coefficient for swirling flows can be made provided the values of the eddy viscosity are available. In the present work the axial and tangential velocity fields are surveyed in a pipe for the determination of eddy viscosity. The data thus obtained were utilised to determine the influence of the axial Reynolds number and swirl number on the eddy viscosity. An empirical relationship is suggested to determine the eddy viscosity as a function of Reynolds number and swirl number.

Turbulence in decaying swirl flow through a pipe is studied experimentally by using a single rotating inclined hot-wire probe and the results are presented in the form of profiles of the three mean velocities and the six components of the stress tensor. The results indicate that all the nine components are very weakly influenced by the Reynolds number, but strongly depend on the initial swirl. The swirling stream develops two regions of flow which are characterized by the variation of the tangential velocity and the Reynolds stresses. It was also found that the turbulence intensities are higher at the core and with the decay of the swirl their magnitudes reduce markedly at the core while they change slightly near the wall.

Swirl flow in a pipe is studied experimentally and the data so obtained have been compared with theoretical predictions computed from a proposed calculation procedure which determines the swirl intensity, tangential and axial velocity distributions by defining only the flow parameters at the inlet of the test pipe.

The excess molar volume and ultrasonic speed have been measured in dipropylene glycol monomethyl ether + butylamine, dibutylamine, and tributylamine across the entire composition range, at the temperature 298.15 K and atmospheric pressure. The ultrasonic speed values have been combined with those of the excess molar volumes converted to densities to give estimates of the product KS,mof the molar volumes and isentropic compressibility κSand the excess quantity KS,mE. The excess volumes are negative over the entire range of composition for all mixtures with the exception of tributylamine. The KS,mEvalues are negative for all mixtures. The deviation of the speeds of sound uDfrom their ideal values uidin an ideal mixture were also calculated for all measured mole fractions. Graphs of VmE, u, uD, and KS,mEagainst composition are presented as a basis for a qualitative discussion of the results.