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BACKGROUND: Patients with malignant pleural effusion (MPE) are usually treated with an indwelling pleural catheter (IPC) or pleurodesis. However, most do not achieve a satisfactory control rate of pleural effusion and have poor prognosis. Distilled water has cytocidal effects of hypotonic shock and can result in the lysis of cancer cells which was used in surgery to eradicate cancer cells. However, there is no study focusing on the efficacy of intrapleural hyperthemic perfusion for MPE under video-assisted thoracoscopic surgery (VATS). This study explored the efficacy and safety of intrapleural hyperthermic perfusion (IHP) with distilled water in patients with MPE. METHODS: In this retrospective, single-arm trial, patients admitted to department of cardiothoracic surgery of Taizhou hospital and diagnosed with MPE caused by non-small cell lung cancer from January 2014 and December 2018 were included. The clinical characteristics including age, gender smoking history, Karnofsky score, volume of pleural effusion, TNM cancer stage, pathology, genetic test of patients were collected. Patients were treated with hyperthermic perfusion. The pleural cavity was perfused with 43.0 ℃ distilled water for 60 minutes under video-assisted thoracic surgery (VATS). The efficacy of treatment was defined as follows: (I) complete remission (CR; no recurrence of pleural effusion after IHP for at least four weeks); (II) partial remission (PR; pleural effusion was decreased by 50% and the condition lasted for 4 weeks; or (III) no remission (NR; no decrease in pleural effusion). Kaplan-Meier method with a log-rank test was used for survival analysis. Cox proportional hazards regression models were applied to perform univariate and multivariate analyses RESULTS: From January 2014 through December 2018, 30 patients with MPE caused by non-small cell lung cancer (NSCLC) were treated with hyperthermic perfusion. There were no serious reportable clinical complications associated with the procedure. The response rate was 96.7%, with 63.3% experiencing PR and 33.3% achieving CR. The overall survival (OS) ranged from 2 to 46 months. The median survival was 12 months. CONCLUSIONS: IHP proved to be a feasible and safe strategy for patients with MPE in our study but it still needs to be verified with a larger, prospective and randomized trial in the future.

Background: Patients with malignant pleural effusion (MPE) have a poor prognosis. Most patients are treated with tube thoracostomy and sclerotherapy but with a not satisfactory control rate of pleural effusion. This study aims to report the effect of intrapleural hyperthermic perfusion for MPE which is a standard practice at our center.Methods: This is a retrospective study of consecutive patients with MPE treated with hyperthermic perfusion from one single Institute. The procedure was done by perfusing the pleural cavity under video-assisted thoracoscope with 43.0°C distilled water using a standard extracorporeal circuit for 60 minutes. The efficacy of treatment was classified as follows: 1. complete response (CR; no re-accumulation of pleural effusion after IPH for at least four weeks); 2. partial response (PR; pleural effusion was reduced by 50% and this situation was sustained for four weeks; 3. no consequence (NC; pleural effusion was not reduced.Results: From January 2014 through December 2018, a total of 31 patients with MPE were treated using this technique. There were no serious reportable clinical complications associated with the procedures. The response rate was 100%, with 67.7% of PR and 32.3% of CR. The survival time ranged from 2 to 46 months, with a median survival of 12 months. The survival time of the patients received TKI treatment after IHP ranged from 13 to 45 months, with a median survival of 28 months. Multivariable analysis showed that TKI treatment (P=0.013) and male gender (P=0.004) were independent prognosis factors.Conclusions: Intrapleural hyperthermic perfusion is a feasible and safe strategy for patients with malignant pleural effusion.

PURPOSE This study aims to compare the incidence of complications when using a new approach to secure an indwelling peripheral venous catheter (PVC), involving tying of the tube with a surgical knot at two places and several layers of elastic adhesive bandage, with a standard approach using sterile, transparent, and protective film. METHODS This study enrolled 311 consecutive adults undergoing thoracoscopic lobectomy under general anesthesia at Taizhou Hospital of Zhejiang Province between October 2017 and May 2018. Patients were randomized to experimental and control groups and were followed for up to 72 hours. The primary endpoint was dislodgement of the PVC. Secondary endpoints were blood in the catheter; analgesia pump obstruction alarm; time taken and cost of PVC replacement; replacement of securing materials and analgesia pump line; and time and cost of replacing them. All adverse events were recorded. FINDINGS Final analysis included 248 patients (experimental group: n = 126; control group: n = 122). PVC dislodgement was less frequent in the experimental group than in the control group. In the control group, 78.7% of patients required replacement of securing materials (costing 37 cents each time) and 13.1% required PVC replacement (costing 3.6 dollars each time), necessitating additional nursing time. No patients in the experimental group required replacement of the PVC or securing materials. Blisters were less common in the experimental group than in the control group (0% vs 9.84%, P < .001). No patients had limb edema. CONCLUSIONS This new method of securing an analgesia pump line can reduce traction on the indwelling PVC, lowering the dislodgement rate.

The texture quality of French fries is critical to the potato processing industry. Sensory evaluation via testing mouth sensation or by visual and finger spinning inspection are the primary methods to assess French fry texture quality. Instrumental texture analysis has not been practically used due to data inconsistency. This study aimed to minimize variations of instrumental analysis and identify instrumental parameters with strong correlations to a sensory evaluation to enhance the effectiveness of the texture quality assessment. This research was carried out on an industrial scale and utilized 10 potato varieties to increase the texture variation of samples. The sensory evaluation by the visual and finger spinning inspection was performed following industrial procedures and standards. Results showed instrumental crispness and crunchiness, as represented by the slope of the first significant fracture and the number of fractures of the force-distance curve in a cut test with a T-42 blade, were strongly correlated with desirable sensory attributes. Microstructure examination revealed that a low level of crust compactness was associated with instrumental crispness and crunchiness. The procedure advanced in this study had a small data variation and concluded that instrumental crispness and crunchiness are strong indicators of premium French fry texture quality.

A distributed control system of Neutral Beam Injector (NBI) on the Experimental Advanced Superconducting Tokamak (EAST-NBI) is brie∞y presented in this paper. The control system is developed in accordance with the experimental operational characteristics of the EAST- NBI. The NBI control system (NBICS), which is based on the computer network technologies and classifled according to the control levels, consists of three levels: a remote monitoring layer, a server control layer, and a fleld control layer. The 3-layer architecture is capable of extending the system functions and upgrading devices. The timing system provides the reference clock of the synchronization and interlock for the EAST-NBI system. An interlock system ensures the safety of the experiment operators and fleld devices. Both of the ion sources of the beamline are designed to operate independently. This lays an important foundation for developing a control system for the second beamline on EAST. Experimental results demonstrate that the NBICS meets functional requirements of the EAST-NBI control, and makes experimental operations visual and automatic.

In order to synchronize the elements of the EAST Neutral Beam Injector (NBI) spatially located in several places, a distributed Timing System (TS) is developed in this paper. The timing system provides a clock reference for synchronization and an interlock protection of the EAST NBI system. It sends timing signals to field devices, controls the pulse widths of the timing sequences, and provides a sampling clock for the Data Acquisition System (DAS). The timing system also generates analog waveforms to control power supplies and gas supplies according to the operator's configuration. The timing system is developed on a PXI (PCI eXtensions for Instrumentation) platform consisting of a LabVIEW workstation and a timing control terminal. The timing control terminal consists of a timing node and several control interface crates. Two timing nodes are configured in one beam line. Each node is responsible for the timing sequence, analog generation and feedback control for one ion source. The architecture and implementation of the timing system are presented in this paper.

Synchronous output of one beam line's two megawatt hot cathode bucket ion sources is required when Neutral Beam Injector (NBI) works on the Experimental Advanced Superconducting Tokamak (EAST). Neutral Beam Injector Control System (NBICS) realizes synchronous output and asynchronous output of two ion sources with network communication and hardware triggers. And the synchronous time can be set by operator. In synchronous mode, two megawatt hot cathode bucket ion sources can produce neutral beams at any relative time with higher energy than two sources' asynchronous output. Two megawatt hot cathode bucket ion sources' synchronous output makes an important contribution to NBI system of 4-8 MW with 10-100 s pulse length and provides more and better parameters for EAST physical experiments.

In this paper, a description of the control system’s software and hardware architecture for the Experimental Advanced Superconducting Tokamak neutral beam injector (NBI) is introduced. The chosen platform is a CPCI-based and PXI-based computerized network system. Three PXI/CPCI crates house several boards for performing analogue signal acquisition, analogue voltage generation, signal conditioning, digital input detection and digital output generation. Two server computers running CentOS 6.3 operating system act as control server and data server respectively. A virtual instrument for the timing system is developed with LabVIEW 2010 on the PXI-based platform. Graphical user interfaces for monitoring and programming purposes are developed with LabVIEW and WinCC integrated development environments by using TCP/IP network protocol under the Windows operating system. Experimental results demonstrate that the visualization and automation of NBI experimental operations are successfully implemented by using the functions of remote monitoring, interlock protection, and data processing.

As the center of neutral beam injector (NBI) control system, main control server controls the whole NBI system’s input and output services, and it verifies whether the experimental parameters are reasonable, stores the real-time data, monitors the statuses of the experimental equipments in real time and makes it easy to perform self-protection and alarm automatically. In order to realize these functions, MYSQL technology, client/server communication mode, multithreading and cyclic redundancy check technology are used in this paper.

The neutral beam injection (NBI) heating is one of the mainly auxiliary plasma heating methods for EAST. In this paper, a data server application software is presented for NBI control system. This application software is developed on Centos OS by C programming language with TCP and multithreading technology. It mainly focuses on storing and querying experimental pulse data and engineering data; experimental user’s operation records; experimental configuration information; the collected data after processing; as well as managing and releasing experimental discharge shot number and so on. By using the unified data header structure, the data server software provides universal information exchange interfaces for different service request terminals with different operating platform, such as WinCC, Labview. With the help of data server software, those problems related on the storage, querying and processing of information and data for NBI control system are well solved.

Primary cilia are required for proper Sonic Hedgehog (Shh) signaling in mammals. However, their role in the signal transduction process remains unclear. We have identified sister of open brain ( sopb ), a null allele of mouse Intraflagellar transport protein 122 ( Ift122 ). IFT122 negatively regulates the Shh pathway in the cilium at a step downstream of the Shh ligand and the transmembrane protein Smoothened, but upstream of the Gli2 transcription factor. Ift122 sopb mutants generate primary cilia, but they show features of defective retrograde intraflagellar transport. IFT122 controls the ciliary localization of Shh pathway regulators in different ways. Disruption of IFT122 leads to accumulation of Gli2 and Gli3 at cilia tips while blocking the ciliary localization of the antagonist TULP3. Suppressor of Fused and Smoothened localize to the cilium through an IFT122-independent mechanism. We propose that the balance between positive and negative regulators of the Shh pathway at the cilium tip controls the output of the pathway and that Shh signaling regulates this balance through intraflagellar transport.

Effects of polyamidoamine (PAMAM) dendrimers on the intestinal absorption of poorly absorbable drugs were examined by an in situ closed loop method in rats. 5(6)-Carboxyfluorescein (CF), fluorescein isothiocyanate-dextrans (FDs) with various molecular weights, calcitonin and insulin were used as model drugs of poorly absorbable drugs. The absorption of CF, FD4 and calcitonin from the rat small intestine was significantly enhanced in the presence of PAMAM dendrimers. The absorption-enhancing effects of PAMAM dendrimers for improving the small intestinal absorption of CF were concentration and generation dependent and a maximal absorption-enhancing effect was observed in the presence of 0.5% (w/v) G2 PAMAM dendrimer. However, G2 PAMAM dendrimer had almost no absorption-enhancing effect on the small intestinal absorption of macromolecular drugs including FD10 and insulin. Overall, the absorption-enhancing effects of G2 PAMAM dendrimer in the small intestine decreased as the molecular weights of drug increased. However, G2 PAMAM dendrimer did not enhance the intestinal absorption of these drugs with different molecular weights in the large intestine. Furthermore, we evaluated the intestinal membrane damage with or without G2 PAMAM dendrimer. G2 PAMAM dendrimer (0.5% (w/v)) significantly increased the activities of lactate dehydrogenase (LDH) and the amounts of protein released from the intestinal membranes, but the activities and amounts of these toxic markers were less than those in the presence of 3% Triton X-100 used as a positive control. Moreover, G2 PAMAM dendrimer at concentrations of 0.05% (w/v) and 0.1% (w/v) did not increase the activities and amounts of these toxic markers. These findings suggested that PAMAM dendrimers at lower concentrations might be potential and safe absorption enhancers for improving absorption of poorly absorbable drugs from the small intestine.

The effects of polyethylene glycol 20000 (PEG 20000) on the intestinal absorption of prednisolone, methylprednisolone and quinidine, three P-glycoprotein (P-gp) substrates, across the isolated rat intestinal membranes were examined by an in-vitro diffusion chamber system. The serosal-to-mucosal (secretory) transport of these P-gp substrates was greater than their mucosal-to-serosal (absorptive) transport, indicating that their net movement across the intestinal membranes was preferentially in the secretory direction. The polarized secretory transport of these drugs was remarkably diminished and their efflux ratios decreased in the presence of PEG 20000. In addition, PEG 20000 did not affect the transport of Lucifer yellow, a non-P-gp substrate. The intestinal membrane toxicity of PEG 20000 was evaluated by measuring the release of alkaline phosphatase (ALP) and protein from the intestinal membranes. The release of ALP and protein was enhanced in the presence of 20 mM sodium deoxycholate (NaDC), a positive control, while these biological parameters did not change in the presence of 0.1–5% (w/v) PEG 20000. These findings indicated that the intestinal membrane damage caused by PEG 20000 was not a main reason for the enhanced absorptive transport of these P-gp substrates in the presence of PEG 20000. Furthermore, the transepithelial electrical resistance (TEER) of rat jejunal membranes in the presence or absence of PEG 20000 was measured by a diffusion chamber method. PEG 20000 (0.1–5.0 % w/v) did not change the TEER values of the rat jejunal membranes, indicating that the increase in the absorptive transport of these P-gp substrates might not be due to the increased transport of these P-gp substrates via a paracellular pathway caused by PEG 20000. Finally, the effect of PEG 20000 on the intestinal absorption of quinidine was examined by an in-situ closed-loop method. The intestinal absorption of quinidine was significantly enhanced in the presence of 0.1-1.0% (w/v) PEG 20000. These findings suggest that PEG 20000 might be a useful excipient to improve the intestinal absorption of quinidine, which is mainly secreted by a P-gp-mediated efflux system in the intestine.

The absorption enhancing effects of polyamines, spermine (SPM), spermidine (SPD) and putrescine (PUT) on the pulmonary absorption of poorly absorbable drugs were studied in rats. Insulin, 5(6)-carboxyfluorescein (CF), and fluorescein isothiocyanate-labeled dextrans (FDs) were chosen as models of poorly absorbable drugs. The absorption of insulin from the lung was enhanced in the presence of SPM and SPD, while PUT had almost no absorption enhancing effect for improving the pulmonary absorption of insulin in rats. SPM also improved the pulmonary absorption of FDs with various molecular weights, although we found almost no significant difference in the pulmonary absorption of CF with or without SPM. As for the pulmonary membrane toxicity of SPM, there was no significant difference in the release of protein and lactate dehydrogenase (LDH) with or without SPM in bronchoalveolar lavage fluid (BALF), indicating that SPM did not cause any membrane damage to the lung tissues. Furthermore, SPM did not affect the stability of insulin in BALF, suggesting that SPM might increase the permeability of insulin across the alveolar epithelium. In conclusion, polyamines, especially SPM can effectively improve the pulmonary absorption of insulin and other macromolecules without any membrane damage to the lung tissues.

Peroxisome proliferator-activated receptors (PPARs) are members of the nuclear receptor superfamily that transcriptionally regulate responsive genes by binding to the peroxisome proliferator response elements. Protein(s) interacting with PPAR isoforms (alpha, delta, and gamma) may modulate the PPAR-mediated transcriptional activation. Using a yeast two-hybrid system to screen a rat liver cDNA library, we have identified rat deoxyuridine-triphosphatase (dUTPase, EC 3.6. 1.23) as a PPARalpha-interacting protein. This cDNA encodes a polypeptide of 203 amino acids; the C-terminal 141-amino acid segment of this protein corresponds to the full-length human enzyme, which exhibits 92% identity with human dUTPase; the N-terminal extra 62-amino acid residue region is arginine-rich. In vitro binding assays indicate that rat dUTPase interacts with all three isoforms of mouse PPAR, but not with retinoid X receptor and thyroid hormone receptor. Interaction of PPARalpha with dUTPase is with the N-terminal 62-amino acid segment of rat dUTPase. Full-length rat dUTPase prevents PPAR-retinoid X receptor heterodimerization resulting in an inhibition of PPAR activity in a ligand-independent manner. Immunostaining of human kidney tsA201 cells, transiently expressing dUTPase showed that this protein is present predominantly in the cytoplasm but translocates into the nucleus with PPARalpha when PPARalpha is coexpressed with dUTPase. Northern blot hybridization shows that rat dUTPase is encoded by an abundant 1kilobase mRNA species present in all rat tissues. The identification of dUTPase as a PPAR-interacting protein suggests a possible link between tumorigenic peroxisome proliferators and the enzyme system involved in the maintenance of DNA fidelity.

Human liver peroxisomes contain two acyl-CoA oxidases, namely, palmitoyl-CoA oxidase and a branched chain acyl-CoA oxidase. The palmitoyl-CoA oxidase (ACOX) oxidizes the CoA esters of straight chain fatty acids and prostaglandins and donates electrons directly to molecular oxygen, thereby producing H2O2. The inducibility of this H2O2-generating ACOX in rat and mouse liver by peroxisome proliferators and the postulated role of the resulting oxidative stress in hepatocarcinogenesis generated interest in characterizing the structure and function of human ACOX. We have constructed a full-length cDNA encoding a 660-amino acid residue human ACOX and produced a catalytically active human ACOX protein at high levels in Spodoptera frugiperda (Sf9) insect cells using the baculovirus vector. Immunoblot analysis demonstrated that the full-length 72-kDa polypeptide (component A) was partially processed into its constituent 51-kDa (component B) and 21-kDa (component C) products, respectively. Recombinant protein (approximately 20 mg/l x 10(9) cells) was purified to homogeneity by a single-step procedure on a nickel-nitrilo-triacetic acid affinity column. Using the purified enzyme, Km and Vmax values for palmitoyl-CoA were found to be 10 microM and 1.4 units/mg of protein, respectively. The maximal activities for saturated fatty acids were observed with C12-18 substrates. The overexpressed human ACOX protein was identified in the cytoplasm of the insect cells by immunocytochemical staining. Individual expression of either the truncated ACOX 51-kDa (component B) or the 21-kDa (component C) revealed lack of enzyme activity, but co-infection of the insect cells with recombinant viruses expressing components B and C resulted in the formation of an enzymatically active heterodimeric B+C complex which could subsequently be inactivated by dissociating with detergent.

The absorption-enhancing effects of polyamidoamine (PAMAM) dendrimers with various generations (G0-G3) and concentrations [0.1%-1.0% (w/v)] on the pulmonary absorption of peptide and protein drugs were studied in rats. Insulin and calcitonin were chosen as models of peptide and protein drugs, and their pulmonary absorption with or without PAMAM dendrimers was examined by in vivo pulmonary absorption studies. PAMAM dendrimers significantly increased the pulmonary absorption of insulin and calcitonin in rats, and their absorption-enhancing effects were generation dependent. The rank order of absorption enhancement effect of these PAMAM dendrimers was G3 > G2 > G1 > G0. For the same generation, the absorption-enhancing effects of PAMAM dendrimers were shown to be concentration dependent. The toxicity of these PAMAM dendrimers in the lung tissues was evaluated by measuring the release of protein and the activities of lactate dehydrogenase (LDH) in bronchoalveolar lavage fluid (BALF). The PAMAM dendrimers with various generations and concentrations did not significantly increase the release of protein and the activities of LDH in BALF, indicating that these dendrimers did not cause any membrane damage to the lung tissues. The zeta potentials of insulin and calcitonin solutions changed to positive by the addition of PAMAM dendrimers, and the degree of positive charge as determined by the zeta potentials was linearly correlated with the absorption-enhancing effects of the PAMAM dendrimers. This positive charge of the PAMAM dendrimers might be related to their absorption-enhancing mechanisms for improving the pulmonary absorption of insulin and calcitonin in rats. In conclusion, the PAMAM dendrimers are suitable absorption enhancers to improve the pulmonary absorption of insulin and calcitonin without any membrane damage to the respiratory tissues.

The effect of Wellsolve, a new solubilizing agent, on the function of intestinal membrane barrier and transporters including P-glycoprotein (P-gp) and peptide transporter (PEPT1) was examined by an in vitro diffusion chamber and an in situ closed loop method. The model drugs used in this study were 5(6)-carboxyfluorescein (CF), rhodamine123 (a P-glycoprotein substrate), cephalexin (a typical substrate for PEPT1) and griseofulvin (a BCS Class II drug). Intestinal absorption of CF was not affected by the addition of 1—10% (v/v) Wellsolve, while 20% (v/v) Wellsolve significantly enhanced its intestinal absorption by the in situ absorption study. Therefore, this finding suggested that high concentration of Wellsolve might alter the intestinal barrier function. The mucosal to serosal (absorptive) and serosal to mucosal (secretory) transport of rhodamine123 was significantly inhibited in the presence of 5.0—20% (v/v) of Wellsolve, suggesting that Wellsolve might not affect the function of P-gp in the intestine. The intestinal transport of cephalexin was not affected in the presence of Wellsolve, suggesting that this solubilizing agent might not change the function of PEPT1 in the intestine. In the toxicity studies, we found that 1—10% (v/v) Wellsolve did not change the release of lactate hydrogenase (LDH) and protein from the intestinal membranes. Furthermore, intestinal absorption of griseofulvin in the presence of 10% (v/v) Wellsolve significantly increased as compared with the control. In summary, Wellsolve at lower concentrations might be a potent and safe solubilizing agent for improving the solubility and absorption of poorly water-soluble drugs including griseofulvin.

The effects of polyethylene glycol 20000 (PEG 20000) on the intestinal absorption of prednisolone, methylprednisolone and quinidine, three P-glycoprotein (P-gp) substrates, across the isolated rat intestinal membranes were examined by an in-vitro diffusion chamber system. The serosal-to-mucosal (secretory) transport of these P-gp substrates was greater than their mucosal-to-serosal (absorptive) transport, indicating that their net movement across the intestinal membranes was preferentially in the secretory direction. The polarized secretory transport of these drugs was remarkably diminished and their efflux ratios decreased in the presence of PEG 20000. In addition, PEG 20000 did not affect the transport of Lucifer yellow, a non-P-gp substrate. The intestinal membrane toxicity of PEG 20000 was evaluated by measuring the release of alkaline phosphatase (ALP) and protein from the intestinal membranes. The release of ALP and protein was enhanced in the presence of 20 mM sodium deoxycholate (NaDC), a positive control, while these biological parameters did not change in the presence of 0.1-5% (w/v) PEG 20000. These findings indicated that the intestinal membrane damage caused by PEG 20000 was not a main reason for the enhanced absorptive transport of these P-gp substrates in the presence of PEG 20000. Furthermore, the transepithelial electrical resistance (TEER) of rat jejunal membranes in the presence or absence of PEG 20000 was measured by a diffusion chamber method. PEG 20000 (0.1-5.0 % w/v) did not change the TEER values of the rat jejunal membranes, indicating that the increase in the absorptive transport of these P-gp substrates might not be due to the increased transport of these P-gp substrates via a paracellular pathway caused by PEG 20000. Finally, the effect of PEG 20000 on the intestinal absorption of quinidine was examined by an in-situ closed-loop method. The intestinal absorption of quinidine was significantly enhanced in the presence of 0.1-1.0% (w/v) PEG 20000. These findings suggest that PEG 20000 might be a useful excipient to improve the intestinal absorption of quinidine, which is mainly secreted by a P-gp-mediated efflux system in the intestine.

We examined the effect of polyethylene glycols (PEGs) with different molecular weights and their derivatives on the intestinal absorption of rhodamine123, a P-glycoprotein (P-gp) substrate, across the isolated rat intestinal membranes by an in vitro diffusion chamber system. The serosal to mucosal (secretory) transport of rhodamine123 was greater than its mucosal to serosal (absorptive) transport, indicating that the net movement of rhodamine123 across the intestinal membranes was preferentially secretory direction. The secretory transport of rhodamine123 was inhibited by the addition of PEGs with average molecular weights of 400, 2000 and 20,000, irrespective of its molecular weight. The inhibitory effects of these PEGs for the intestinal P-gp function were concentration dependent over the range 0.1-20% (v/v or w/v). Similar inhibitory effect for the intestinal P-gp function was observed when PEG derivatives including PEG monolaurate, PEG monooleate and PEG monostearate were added to the mucosal site of the chambers. Furthermore, we also examined effect of PEG20,000 on the intestinal absorption of rhodamine123 by an in situ closed loop method. The intestinal absorption of rhodamine123 was enhanced in the presence of PEG20,000. These findings suggest that PEGs and their derivatives are useful excipients to inhibit the function of intestinal P-gp, thereby improving the intestinal absorption of P-gp substrates, which are secreted by a P-gp-mediated efflux system.

Peroxisome proliferator-activated receptor (PPAR) forms a heterodimer with retinoid X receptor (RXR) that binds to the peroxisome proliferator responsive element (PPRE) to regulate the expression of target genes. PPRE of the rat enoyl-CoA hydratase/3-hydroxyacyl-CoA dehydrogenase (HD) gene has previously been shown to consist of three imperfect TGACCT half-sites and form two distinct complexes (C1 and C2) with the nuclear extracts from H4IIEC3 cells. The present study identifies another imperfect TGACCT motif involved in the PPAR/RXR-mediated trans-activation process and demonstrates that these four imperfect TGACCT motifs constitute an unique binding site consisting of two DR1 elements overlapping a DR2 element. PPAR and RXR cooperatively bind the two DR1 elements to form C1 complex or bind DR2 element to form C2 complex with a 1:1 ratio. Saturation of the HD PPRE probes with receptor proteins cannot convert the heterodimeric C2 complex to the higher order C1 complex, suggesting that they are formed independently. Transfection analyses indicate that mutation of any one of these TGACCT motifs or truncation of the entire HD PPRE into a separate DR1 and DR2 element significantly reduced the transcriptional response of HD PPRE to peroxisome proliferators. The rat HD PPRE differentially binds with one or two PPAR/RXR heterodimers providing the peroxisome proliferator signaling pathway with two levels of response.