Rapamycin attenuates liver graft injury in cirrhotic recipient--the significance of down-regulation of Rho-ROCK-VEGF pathway

To investigate whether rapamycin could attenuate hepatic I/R injury in a cirrhotic rat liver transplantation model, we applied a rat orthotopic liver transplantation model using 100% or 50% of liver grafts and cirrhotic recipients. Rapamycin was given (0.2 mg/kg, i.v.) at 30 min before graft harvesting in the donor and 24 h before operation, 30 min before total hepatectomy and immediately after reperfusion in the recipient. Rapamycin significantly improved small-for-size graft survival from 8.3% (1/12) to 66.7% (8/12) (p = 0.027). It also increased 7-day survival rates of whole grafts (58.3%[7/12] vs. 83.3%[10/12], p = 0.371). Activation of hepatic stellate cells was mainly found in small-for-size grafts during the first 7 days after liver transplantation. Rapamycin suppressed expression of smooth muscle actin, which is a marker of hepatic stellate cell activation, especially in small-for-size grafts. Intragraft protein expression and mRNA levels of vascular endothelial growth factor (VEGF) were down-regulated by rapamycin at 48 h both in whole and small-for-size grafts. Consistently, mRNA levels and protein expression of Rho and ROCK I were decreased by rapamycin during the 48 h after liver transplantation. In conclusion, rapamycin attenuated graft injury in a cirrhotic rat liver transplantation model by suppression of hepatic stellate cell activation, related to down-regulation of Rho-ROCK-VEGF pathway.

Fat-derived hormone adiponectin combined with FTY720 significantly improves small-for-size fatty liver graft survival

Owing to the discrepancy between organ donation and the demand for liver transplantation, expanding the liver donor pool is of vital importance. However, marginal liver grafts, such as small-for-size and/or fatty grafts, were associated with primary graft nonfunction or poor function. Therefore, novel combination therapies to rescue small-for-size fatty liver grafts should be investigated. In this study, we applied a combination therapy using a fat-derived hormone adiponectin (anti-steatosis) plus immunomodulator FTY720 (anti-inflammatory) in a rat liver transplantation model using small-for-size fatty liver grafts, and investigated the underlying protective mechanism such as anti-steatosis, intra-graft energy metabolism, hepatic microcirculatory changes, cell signaling cascades for survival, apoptosis and inflammation. The current study demonstrated that even a single treatment of adiponectin or FTY720 improved the 7-day graft survival from 0% to 62.5% (p = 0.001). The combination therapy significantly increased the 7-day graft survival rate to 100% by remarkable attenuation of graft steatosis and acute phase inflammatory response, significant activation of cell survival Akt pathway and maintenance of intra-graft adenosine triphosphate metabolism and improvement of hepatic microcirculation. In conclusion, the fat-derived hormone adiponectin combined with FTY720 might be a novel combination drug therapy for prevention of small-for-size fatty liver graft injury.

Drought-inducible-but ABA-independent-thaumatin-like protein from carrot (Daucus carota L.)

Drought treatment induces the accumulation of dcTLP, which is similar in structure to the thaumatin-like proteins (TLPs) found in the embryogenic calli, seedlings, and mature plants of carrot (Daucus carota). We isolated a full-length dcTLP cDNA clone from carrot and characterized the 5' upstream sequences. The coding region of dcTLP consisted of 645 nucleotides; the theoretical pI value was 4.9, and its molecular weight was approximately 22 kDa. The production of dcTLP transcripts in the seedlings increased dramatically with dehydration treatment but was not affected by abscisic acid (ABA), salicylic acid, or jasmonic acid. The expression patterns of dcTLP mRNA at different developmental stages and in response to a variety of signal molecules was analyzed using reverse transcriptase-PCR and promoter analysis with fused genes of 0.5-kb 5' upstream sequences in which beta-glucuronidase (GUS) reporter genes (gus) were established. The induction of dcTLP was found to be highly specific to drought stress in the embryogenic calli, seedlings, and mature plants. Our results suggest that this new isoform of TLP that has been isolated from carrot is a drought-specific, ABA-independent, non-organ-specific, and non-developmental-stage-specific protein.

Generalizability and persistence of a multifaceted intervention for improving quality of care for rural patients with type 2 diabetes

OBJECTIVE

Most quality improvement efforts for type 2 diabetes have neglected cardiovascular risk factors and are limited by a lack of information about generalizability across settings or persistence of effect over time.

RESEARCH DESIGN AND METHODS

We previously reported 6-month results of a controlled study of an intervention that improved cardiovascular risk factors for rural patients with type 2 diabetes. We subsequently provided the identical intervention to the control region after the main study was completed. The primary outcome was 10% improvement in systolic blood pressure, total cholesterol, or HbA(1c). We compared the previously reported 6-month effect of the original intervention with the effect of the crossed-over intervention to the former control region and remeasured outcomes in the original intervention region 12 months later.

RESULTS

Our analysis included 200 original intervention and 181 crossed-over intervention subjects. The age of the population was 62.4 +/- 12.4 years (mean +/- SD), and 54.3% were women. A similar proportion of patients in the crossed-over intervention group achieved improvement in the primary composite outcome compared with the original intervention group (38 vs. 44%, respectively; P = 0.29). In adjusted analyses, we observed less improvement in blood pressure (adjusted odds ratio 0.40 [95% CI 0.17-0.75]) but greater improvements in total cholesterol (1.86 [0.93-3.7]) with the crossed-over intervention compared with the original intervention. We observed sustained improvements in total cholesterol and HbA(1c) levels in the original intervention group, whereas previous large gains in control of blood pressure diminished over time.

CONCLUSIONS

We found that our intervention was generalizable across settings, and its effect persisted over time. Nevertheless, without ongoing intervention or reinforcement, we noted some loss of the original benefits that had accrued. Future translational work should incorporate interventions such as ours into ongoing systems of rural care.

Enhancement of pairing correlation by t' in the two-dimensional extended t-J model

We investigate the effects of the next-nearest-neighbor (t') and the third-nearest-neighbor (t") hopping terms on superconductivity correlation in the 2D hole-doped extended t-J model based on the variational Monte Carlo, mean-field calculation and exact diagonalization method. Despite the diversity of the methods employed, the results all point to a consistent conclusion: While the d-wave superconductivity correlation is slightly suppressed by t' and t" in underdoped regions, it is greatly enhanced in the optimal and overdoped regions. The optimal Tc is a result of the balance of these two opposite trends.

Improvements in patient-reported outcomes associated with an intervention to enhance quality of care for rural patients with type 2 diabetes: results of a controlled trial

OBJECTIVE

The aim of this study was to examine patient-reported outcomes in a controlled trial of a multifaceted provider-level intervention to improve quality of care for rural patients with type 2 diabetes.

RESEARCH DESIGN AND METHODS

We conducted a before/after intervention study with concurrent controls in two rural regions in Alberta, Canada. The intervention consisted of six monthly visits by a multidisciplinary health care team and was primarily directed at primary care providers. Clinical and patient-reported outcomes were assessed after 6 months. Patient-reported outcomes included changes in health-related quality of life (Health Utilities Index Mark 3 [HUI3]), satisfaction with care, lifestyle (Diabetes Lifestyle Form), and adherence to self-care activities. Analysis of covariance was used to assess differences over time between the control and intervention regions.

RESULTS

A total of 200 intervention and 172 control subjects were included in this analysis. After adjusting for important clinical and demographic differences, a statistically significant and clinically important improvement in the overall HUI3 score was seen at the 6-month follow-up in the intervention region (0.06 [95% CI 0.02-0.10]) compared with the control region (0.01 [-0.04 to 0.04]) (P = 0.03 for the difference between groups). Satisfaction with general medical care (P < 0.001 between groups) and diabetes care (P < 0.001 between groups) increased among patients in the intervention region compared with the control region. Self-efficacy, attitudes, and beliefs about diabetes control all increased in the intervention region when compared with the control region, but adherence to self-care activities did not.

CONCLUSIONS

A provider-level intervention directed at improving quality of clinical care for patients with type 2 diabetes also had a favorable impact on overall health-related quality of life, satisfaction with care, and other humanistic outcomes.

Treatment gaps for hypertension management in rural Canadian patients with type 2 diabetes mellitus*1

BACKGROUND

There were a reported 2.2 million Canadians living with diabetes mellitus (DM) in 2002, of whom 1.98 million (90.0%) had type 2 DM. In addition, there are approximately 60,000 new cases of type 2 DM diagnosed in Canada each year. However, the research shows that evidence and guidelines for management of hypertension in DM are not always translated into clinical practice. In rural areas, factors affecting implementation of recommendations and/or guidelines are less well understood, although some studies suggest that urban practices provide higher quality of care overall than rural areas.

OBJECTIVE

The goal of this study was to describe the patterns of medication use for hypertension for patients with type 2 DM in rural northern Alberta, Canada. We also tried to identify treatment gaps and opportunities for prescribing antihypertensives relative to the Canadian Diabetes Association's 1998 Clinical Practice Guidelines for the Management of Diabetes in Canada and the Canadian Hypertension Society Recommendations Working Group's 2003 Canadian Recommendations for the Management of Hypertension: Therapy.

METHODS

This study was conducted at the Institute of Health Economics and the University of Alberta (Edmonton, Alberta, Canada). We collected information from a cohort of patients aged >or =20 years with type 2 DM living in 2 adjacent rural regions of northern Alberta, Canada, at the time of enrollment in a diabetes care quality-improvement program as part of the Diabetes Outreach Van Enhancement (DOVE) study. Treatment gaps were determined by comparing antihypertensive pharmacotherapy with a blood pressure (BP) target of < or =130/< or =85 mm Hg. We used multivariate regression analyses to determine the associations between sociodemographic and clinical characteristics and treatment gaps.

RESULTS

A total of 392 patients (229 women, 164 men; mean [SD] age, 62.3 [12.5] years) with type 2 DM were included in this analysis. Patients had a mean (SD) duration of diabetes of 8.3 (8.5) years. A total of 75.8% (297/392) of the study population had hypertension, and most (236/392[60.2%]) were receiving some pharmacotherapy. Treatment gaps were present; 42.7% (n = 67) of patients not receiving pharmacotherapy for hypertension were above the established BP targets. For patients receiving monotherapy, 70% were not at BP targets. For patients receiving dual, triple, and > or =4 medications, 65%, 66%, and 46%, respectively, were not at BP targets. After controlling for systolic blood pressure, male sex (adjusted odds ratio [aOR], 2.17; 95% CI, 1.17-4.03), older age (aOR, 1.80 per decade; 95% CI, 1.51-2.09), lower self-reported physical health (aOR, 0.68; 95% CI, 0.41-0.96), higher body mass index (aOR, 1.05; 95% CI, 1.01-1.10), and past/current smoking (aOR, 1.95; 95% CI, 1.01-3.76) were all significantly associated with a lack of treatment for hypertension.

CONCLUSIONS

Treatment maps in the management of hypertension exist in these rural Canadian patients with type 2 DM. Cardiovascular risk may be underestimated in these patients, particularly among younger patients and women, and those with multiple non-DM risk factors. These are patient subgroups that should be targeted as opportunities to improve hypertension management at the population level.

Underuse of aspirin in type 2 diabetes mellitus: Prevalence and correlates of therapy in rural Canada

BACKGROUND

Patients with type 2 diabetes mellitus (DM) have a markedly increased risk of cardiovascular morbidity and mortality. Guidelines of both the American and Canadian Diabetes Associations recommend the use of aspirin as antiplatelet therapy for all adults with type 2 DM.

OBJECTIVES

The aims of this study were to assess the rate of adherence to guidelines for aspirin use in DM patients in rural Canadian communities and to describe the independent correlates of aspirin use in this population.

METHODS

We collected information from a cohort of patients with type 2 DM living in 2 rural regions of northern Alberta, Canada, at the time of their enrollment in a multidisciplinary outreach program designed to improve their quality of care. Our primary outcome was self-reported use of antiplatelet therapy (aspirin or others). We use multivariate logistic regression analyses to examine the independent association between sociodemographic and clinical characteristics and self-reported use of antiplatelet agents.

RESULTS

Among 342 patients included in the study (who were typical of rural Canadian patients with type 2 DM), the mean age was 62.9 years; 149 (44%) were men, 84 (25%) were of indigenous origin, and the median time since diagnosis of DM was 8 years. Despite guideline recommendations, only 23% of the cohort (78 patients) were regularly taking aspirin alone or in combination with a thienopyridine (n = 74 and n = 2, respectively) or a thienopyridine alone (n = 2). The results of them ultivariate analyses showed that the only factors independently associated with the use of antiplatelet therapy were symptomatic coronary artery disease (adjusted odds ratio [AOR], 3.1; 95% CI, 1.1-8.7; P=0.033 ), older age (AOR, 2.0 per 10-year interval; 95% CI, 1.7-2.2; P<0.001 ); and male sex (AOR, 1.9; 95% CI, 1.1-3.5; P=0.026 ).

CONCLUSIONS

Aspirin is a safe, inexpensive, and readily available therapy that is effective for preventing cardiovascular disease, and patients with type 2 DM are particularly likely to benefit from such preventive therapy. However, we found significant underuse of aspirin therapy among our study population. Aspirin should be included and better promoted as a factor in high-quality, evidence-based DM management.

Misidentification of Aeromonas veronii biovar sobria as Vibrio alginolyticus by the Vitek system

AIMS

To find the cause of misidentification of aeromonads when using the Vitek system.

METHODS AND RESULTS

Two Aeromonas veronii biovar sobria isolates were misidentified as Vibrio alginolyticus by the Vitek system. Both strains' identification was confirmed by biochemical testing, API 20E/20NE kits and/or 16S RFLP analysis. Thirty-one known Aeromonas species were tested by the Vitek system using 0.45 and 0.85% saline in the suspension medium. It was not clear whether low salinity causes misidentification of Aeromonas species more frequently.

CONCLUSIONS

The specified reaction time may be inappropriately short for some critical biochemical tests of some strains. An ingenious reading strategy regarding incubation time is necessary to improve identification of Aeromonas species by the Vitek system.

SIGNIFICANCE AND IMPACT OF THE STUDY

To our knowledge, this is the first report of misidentification of A. veronii biovar sobria as V. alginolyticus in the Vitek system.

Controlled trial of a multifaceted intervention for improving quality of care for rural patients with type 2 diabetes

OBJECTIVE

Despite good evidence and clinical practice guidelines, studies document that treatment of type 2 diabetes is less than optimal. Lack of resources or limited access may put patients in rural communities at particular risk for suboptimal care.

RESEARCH DESIGN AND METHODS

We conducted a prospective, before/after study with concurrent controls to assess the effectiveness of a multidisciplinary diabetes outreach service (intervention) for improving the quality of care for rural patients with type 2 diabetes. Our intervention consisted of six monthly visits by a traveling team of specialist physicians, nurses, dieticians, and a pharmacist. The core of this service was specialist-to-rural primary care physician academic group detailing. Two comparable regions in Northern Alberta were randomly allocated to control or intervention. Data were collected before and 6 months after intervention in a representative volunteer sample. The primary outcome was a 10% improvement in any one of the following: blood pressure, total cholesterol, or HbA(1c).

RESULTS

Our analysis included 200 intervention and 179 control subjects; 14 subjects were at all three primary outcome targets at baseline. The intervention was associated with a trend toward improvement in primary outcome at 6 months (44% intervention vs. 37% control; odds ratio 1.32, 95% CI 0.87-1.99). The intervention was associated with a significant improvement in blood pressure (42% intervention vs. 25% control, P = 0.004); however, there were only small, nonsignificant changes in cholesterol or HbA(1c). The intervention was associated with a significant increase in satisfaction with diabetes care. Multivariate adjustment for baseline differences between intervention and control subjects did not affect any of the main results.

CONCLUSIONS

A diabetes outreach service has the potential to improve the quality of diabetes care for rural patients. Future studies need to involve longer timelines and larger sample sizes.

Cytokine profiles in patients receiving wide-field + prostate boost radiotherapy (xRT) for adenocarcinoma of the prostate

As a result of the association between ionizing irradiation and the induction of inflammatory and fibrogenic cytokines, circulating levels of IL-1alpha, macrophage colony stimulating factor (M-CSF) and TGFbeta were measured in a group of 37 patients who presented with well-defined adenocarcinoma of the prostate and were treated with wide-field pelvic (WFP) + prostate boost (PB) radiotherapy (xRT) according to RTOG protocols 94-08 and 94-13. First and foremost, patients with prostate cancer (PC) were found to have a significantly (p<0.05) elevated plasma level of the three cytokines prior to treatment. Moreover, during WFP + PB xRT, these circulating cytokine levels were further elevated, the elevation occurring in the form of cyclic waves; the concurrent waves of elevated IL-1alpha and M-CSF preceding that of TGFbeta. In addition to providing support for the existence of a humoral response to xRT in patients receiving WFP + PB xRT, the data demonstrated a significant correlation between the integral radiation dose (ID) and the temporal expression and magnitude of plasma IL-1alpha, M-CSF and TGFbeta levels in patients that had received 1-5 fractions (1.8-9Gy) of WFP + PB xRT. Thereafter, the appearance of elevated waves of cytokine expression in the patient's plasma continued independent of additional fractions of WFP + PB xRT.

Low-energy spectra in t-J-type models at low doping levels

Based on a variational approach, we propose that there are two kinds of low-energy states in the t-J-type models at low doping. In a quasiparticle state an unpaired spin bound to a hole with a well-defined momentum can be excited with spin waves. The resulting state shows a suppression of antiferromagnetic order around the hole with the profile of a spin bag. These spin-bag states with spin and charge or hole separated form a continuum of low-energy excitations. Very different properties predicted by these two kinds of states explain a number of anomalous results observed in the exact diagonalization studies on small clusters up to 32 sites.

Two cases of steakhouse syndrome associated with nutcracker esophagus

The most common type of esophageal food-related foreign body is the meat bolus, which is frequently associated with underlying esophageal stenosis. Herein, we report two cases of meat bolus impaction associated with nutcracker esophagus. In the first case, the 63-year-old male patient had chest discomfort and swallowing difficulty after ingestion of butcher's meat. In the second case, the 55-year-old male patient had complained of swallowing difficulty after ingestion of chicken. In both cases, no pathologic findings were observed endoscopically after removal of the esophageal meat bolus. We performed esophageal manometry, which showed very high amplitudes of esophageal pressure in the mid- and distal esophagus. These findings were consistent with nutcracker esophagus. These cases show that esophageal motility disorder may be the cause of esophageal foreign body impaction, and esophageal manometry should be performed for evaluation of the cause of foreign body, especially in an endoscopically normal patient.

Theory for slightly doped antiferromagnetic mott insulators

New trial wave functions, constructed explicitly from the unique Mott insulating state with antiferromagnetic order, are proposed to describe the ground state of a Mott insulator slightly doped with holes or electrons. A rigid band is observed as charged quasiparticles with well-defined momenta being realized in these states. These states have much less superconducting correlations than previously studied ones. Small Fermi patches obtained are consistent with recent experiments on high T(c) cuprates doped lightly with holes or electrons.

Regional cerebral blood flow changes in patients with intractable obsessive compulsive disorders treated by limbic leukotomy

The object of this study is to assess the changes in regional cerebral blood flow (rCBF) following stereotactic limbic leukotomy in patients with medically intractable Obsessive-Compulsive Disorder (OCD). Technetium-99-Hexa Methyl Propylene Amine Oxime (99mTc-HMPAO) Single Photon Emission Computed Tomography (SPECT) data obtained before and after limbic leukotomy were subjected to image fusion with MRI images. Eight samples were obtained from healthy voluteers. After localization of the ROI (Region Of Interest) in anatomical area, rCBF measurements were obtained by METLAB. The results of this study show a change of rCBF following limbic leukotomy in intractable OCD. Postoperative 99mTc-HMPAO SPECT findings implicate the medial frontal cortex, cingulate and striatum, which culd be linked to limbic leukotomy that blocks the functional connection of corticolimbic loop.

A guided simulated annealing method for crystallography

A new optimization algorithm, the guided simulated annealing method, for use in X-ray crystallographic studies is presented. In the traditional simulated annealing method, the search for the global minimum of a cost function is only determined by the ratio of energy change to the temperature. This method designs a new quality function to guide the search for a minimum. Using a multiresolution process, the method is much more efficient in finding the global minimum than the traditional method. Results for two large molecules, isoleucinomycin (C(60)H(102)N(6)O(18)) and an alkyl calix (C(72)H(112)O(8). 4C(2)H(6)O), with different space groups are reported.

Anesthesiology Point of Care project

We are developing a dynamic prototype visual communication system for the operating room environs. This has classically been viewed as an isolated and impenetrable workplace. All medical experiences and all teaching remain in a one to one closed loop with no recall or subsequent sharing for the training and education of other colleagues. The "Anesthesia Point of Care" (APOC) concept embraces the sharing of, recording of, and presentation of various physiological and pharmacological events so that real time memory can be shared at a later time for the edification of other colleagues who were not present at the time of the primary learning event. In addition it also provides a remarkably rapid tool for fellow faculty to respond to obvious stress and crisis events that can be broadcast instantly at the time of happening. Finally, it also serves as an efficient and effective means of paging and general communication throughout the daily routines among various healthcare providers in anesthesiology who work as a team unit; these include the staff, residents, CRNAs, physician assistants, and technicians. This system offers a unique opportunity to eventually develop future advanced ideas that can include training exercises, presurgical evaluations, surgical scheduling and improvements in efficiency based upon earlier than expected case completion or conversely later than expected case completion and even as a unique window to development of improved billing itemization and coordination.

Correlations between peripheral differential leukocyte counts and carotid atherosclerosis in non-smokers

Substantial evidence clearly indicates the immuno-inflammatory nature of atherosclerosis and the important roles of monocytes and other leukocytes in atherogenesis. The relationship between atherosclerosis and the peripheral monocyte count, however, has been equivocal and uncertain so far. One possible reason may be an opposing effect of different major risk factors of atherosclerosis on the monocyte count, e.g. smoking increases the monocyte count while hypercholesterolemia is accompanied by a lower monocyte count. Since smoking is well shown to increase leukocyte counts prominently in weeks, our study included only non-smokers who participated in a health check program at our hospital from 1996 to 1998 and had received a carotid duplex study with extra payment. Our results revealed the followings: In male non-smokers (n=571), the presence of carotid atherosclerosis was associated with significant increases in the counts of all leukocyte, neutrophil, and monocyte (P<0.005,<0.001 and <0.05, respectively), and, after adjustments for age and body mass index, there were significant positive links between these three leukocyte counts and the severity of carotid atherosclerosis, judged by either the sum score of all carotid plaques or the score of the most severe carotid plaque. On the contrary, in female non-smokers (n=614), there was no significant link between differential leukocyte counts and either the presence or severity of carotid atherosclerosis. These results are compatible with recently recognized sex differences in the mechanism and pathophysiology of atherosclerosis, and together with relevant results in the literature, suggest that monocytes and neutrophils are the main types of leukocytes involved in atherosclerosis.

Controlling biofilm and microbial contamination in dental unit waterlines

Despite the fact that the ADA had set the goal of less than 200 colony-forming units per milliliter of unfiltered output water from dental unit waterlines to be achieved voluntarily by the year 2000, there is much confusion and resistance within the profession with regard to waterlines. Many in the profession are still wondering what the most effective means are to predictably achieve the goal. It is a well-established fact that bacterial biofilm can readily form within dental unit waterlines and degrade the microbial quality of the water in dental units regardless of the water source. These biofilms are primarily formed by various microcolonies of bacteria that attach to surfaces over time within the waterlines. An increasing number of medically compromised and immunocompromised patients being treated in dental offices and increased public awareness have brought about renewed interest in this issue. There are generally four categories of products that are available to address this issue: independent water systems, sterile water delivery systems, filtration, and chemical treatment protocols. A recent study at the University of California at Los Angeles demonstrates that the Ultra chemical treatment protocol can be an effective means of controlling biofilm in dental unit waterlines.

Lignification induced by pseudomonads harboring avirulent genes on Arabidopsis

The responses of Arabidopsis thaliana ecotypes to the bacterial pathogen Pseudomonas syringae pv. maculicola 4326 (Psm4326) harboring cloned avirulence genes avrB and avrRpt2 from P. syringae pv. glycinea were examined. Psm4326 containing avirulent genes, avrB and avrRpt2 induced lignification and peroxidase activities in the bacteria infiltrated leaves of Col-O only and not in Mt-O, Bla-2 and Po-1. However, Arabidopsis ecotypes infiltrated with Psm4326 harboring with and without avirulent genes all showed differential induction of mRNA for peroxidase gene and lignin accumulation up to 24 h after infiltration. Only avrB gene in Col-O showed strong corelationship between peroxidase mRNA expression as well as lignification gradually up to 36 h after infiltration. These results extend previous observations that avirulence genes from pathogens of one host plant can be recognized by non-host plants and provide the genetic framework for analysis of the plant-specific response to the bacterial avirulent gene products in A. thaliana.

Intracellular glutathione regulates taurocholate transport in HepG2 cells

The hepatic organic anion transporter 1, Oatp1, was recently demonstrated to function as a GSH exchanger, indicating that hepatic uptake of drugs and xenobiotics may be sensitive to intracellular GSH levels. The present study characterized taurocholate uptake and efflux mechanisms in HepG2 cells and the effects of intracellular GSH on these transport processes. Taurocholate uptake into HepG2 cells was Na(+)-independent, saturable ( K(m) = 82 +/- 16 microM), and was cis-inhibited by bromosulfophthalein and some bile acids. Intracellular GSH depletion inhibited 3H-taurocholate uptake, and, conversely, the release of GSH from HepG2 cells was stimulated in the presence of extracellular taurocholate and other bile acids, consistent with a role for intracellular GSH in stimulating organic anion uptake. Interestingly, efflux of 3H-taurocholate from HepG2 cells was also sensitive to intracellular GSH concentration: efflux was inhibited in cells with lower intracellular GSH and stimulated in cells with higher GSH. RT-PCR analysis revealed that OATP-A, OATP-D, OATP-E, OATP-8, MRP1, MRP2, and MRP3 are expressed in HepG2 cells but that their expression is not altered by the maneuvers used to lower or raise intracellular GSH. These results provide direct evidence that intracellular GSH levels modulate both uptake and efflux of taurocholate and suggest that GSH plays a regulatory role in the hepatobiliary transport of potentially toxic organic compounds.

Gene delivery using a receptor-mediated gene transfer system targeted to hepatocellular carcinoma cells

For gene therapy to be effective in cancers, it is necessary to deliver therapeutic genes into cells with high specificity and efficiency. In this study, we examined the in vitro and in vivo gene delivery efficiency of a new, growth receptor-mediated gene transfer system in hepatocellular carcinoma (HCC). The effects of transfection of wild-type p53 using this system were also studied. The system consisted of a ligand oligopeptide for epidermal growth factor receptor (EGFR) recognition, a polypeptide for DNA binding, and an endosome-releasing oligopeptide for endosomolysis. Two human HCC cell lines and a normal liver cell line were used, and pCMV-beta-galactosidase (beta-gal) was used as a reporter gene. Both HCC cell lines had strong expression of EGFR and the in vitro transfer efficiency peaked at day 5 at about 50%. This finding was in contrast to the normal liver cell line, which had weak EGFR expression and less than 1% transfer efficiency throughout. For in vivo gene transfer in tumors produced by inoculating HCC cells in nude mice and with the vector-beta-gal gene complex injected peritumorally, beta-gal expression was detected within the tumors at 12 hr, peaked at day 5 involving about 50% of the tumor cells and persisted at 2 weeks. Using this vector system, transfection of wild-type p53 into Huh-7 cells that had mutated p53 resulted in significant growth inhibition of cancer cells accompanied by a decreased G2/M phase and increased p53 protein. In conclusion, this receptor-mediated gene transfer system appears to work specifically in HCC cells with high efficiency, and may be promising in delivering apoptotic and other genes into HCC cells.