Comparison of enantioselective disposition of rabeprazole versus lansoprazole in renal-transplant recipients who are CYP2C19 extensive metabolizers

The purpose of this study was to investigate the comparative pharmacokinetics of rabeprazole and lansoprazole enantiomers in renal-transplant recipients on tacrolimus who were CYP2C19 extensive metabolizers. Sixteen Japanese patients were randomly assigned after renal transplantation to receive repeated doses of one of the following two regimens for 28 days; tacrolimus, mycophenolate mofetil and prednisolone together with either 20mg of racemic rabeprazole (n=8) or 30 mg of racemic lansoprazole (n=8). The mean Cmax and AUC0-24 of (R)-lansoprazole compared to (S)-lansoprazole in renal transplant recipients were 12-fold (954+/-522 vs. 167+/-137 ngml(-1), respectively) and 6.9-fold (4787+/-3454 vs. 451+/-354 nghml(-1), respectively) greater, and its elimination half-life was 2.1-fold (2.3+/-1.0 vs. 1.2+/-0.6h, respectively) longer. In contrast, although the elimination half-life of (R)-rabeprazole was significantly longer than that of the (S)-enantiomer (2.1+/-0.5 vs. 1.3+/-0.9h, respectively; P<0.05), there was no difference in Cmax between the (R)- and (S)-enantiomer (186+/-40 vs. 200+/-92 ngml(-1), respectively). In conclusion, in renal-transplant recipients who are CYP2C19 extensive metabolizers, there is less stereoselective difference in the pharmacokinetic disposition between the (R)- and (S)-enantiomers of rabeprazole than those of lansoprazole.

Immune modulation and expression of cytokine genes in rainbow trout Oncorhynchus mykiss upon probiotic feeding

This study elucidates the immune modulation including the expression of cytokine genes following dietary administration of three selected probiotic bacteria--Lactobacillus rhamnosus, Enterococcus faecium and Bacillus subtilis to fish, rainbow trout Oncorhynchus mykiss. They were fed for 45 days on either a basal control diet or one of the three probiotic diets containing the specific bacteria in freeze-dried form at a density of 10(9)CFUgfeed-1. The non-specific immune parameters examined--superoxide anion production by the head kidney leukocytes and the alternate complement activity of serum was improved by probiotic feeding. Besides this, the relative gene expressions of interleukin-1beta1, tumor necrosis factor 1 and 2 and transforming growth factor-beta were up regulated in the spleen and the head kidney. The comparatively better performance of E. faecium could possibly be linked to their suitable ambient temperature conditions. Thus, probiotic bacteria delivered in feed exerts its influence on the immune system of fish, both at cellular and molecular levels.

Influence of ABCB1 C3435T polymorphism on the pharmacokinetics of lansoprazole and gastroesophageal symptoms in Japanese renal transplant recipients classified as CYP2C19 extensive

OBJECTIVE

Lansoprazole and tacrolimus are substrates of ATP binding cassette (ABC) transporters such as P-glycoprotein (ABCBI/multidrug resistance 1) and cytochrome P450 (CYP). The purpose of this study was to investigate the implication of the ABCB1 C3435Tpolymorphism on the pharmacokinetics of (R)-lansoprazole, the major enantiomer, in CYP2C19 extensive metabolizers (EMs) and on gastroesophageal symptoms in renal transplant recipients receiving tacrolimus.

MATERIALS

24 recipients who were CYP2C19 EMs were studied.

METHODS

Oral administration of 30 mg lansoprazole was started 2 days before transplantation. On Day 2 before and Day 28 after transplantation, the plasma concentrations of (R)-lansoprazole and tacrolimus were measured.

RESULTS

Pretransplantation, there were no significant differences in the pharmacokinetic parameters of (R)-lansoprazole between the 3 ABCBI C3435T genotypes. However, after renal transplantation, the peak plasma concentration (Cma ) and area under the plasma concentration-time curve (AUCO-24) of (R)-lansoprazole in patients with the ABCB1 C3435T C allele significantly increased, but not in patients with the TT genotype. These pharmacokinetic variations in (R)-lansoprazole did not influence the AUC of tacrolimus. There were no significant differences in the frequency of gastroesophageal symptoms among the three ABCB] C3435Tgenotypes.

CONCLUSIONS

(R)-lansoprazole concentrations significantly increased in CYP2C19 extensive metabolizers with the ABCB1 C3435T C allele, but not TT genotype, after renal transplantation. However, the clinical relevance of this observation may be minor because these pharmacogenetic changes were not associated with the occurrence of gastroesophageal complications.

Multicentre prospective study of perinatal depression in Japan: incidence and correlates of antenatal and postnatal depression

A multicentre study on the epidemiology of perinatal depression was conducted among Japanese women expecting the first baby (N = 290). The incidence rate of the onset of the DSM-III-R Major Depressive Episode during pregnancy (antenatal depression) and within 3 months after delivery (postnatal depression) were 5.6% and 5.0%, respectively. Women with antenatal depression were characterised by young age and negative attitude towards the current pregnancy, whereas women with postnatal depression were characterised by poor accommodation, dissatisfaction with sex of the newborn baby and with the emotional undermining. Antenatal depression was a major risk factor for postnatal depression.

Short communication: Is intrapartum temporary pacing required for women with complete atrioventricular block? An analysis of seven cases

Women with complete atrioventricular heart block without a permanent pacemaker normally receive temporary pacing for labour and birth. Here, we report seven women who were managed without pacing. All women had a temporary pacing lead inserted prior to induction of labour, but none of the women required pacing during labour or birth. Our experience suggests that women with complete atrioventricular block and without permanent pacing do not routinely require temporary pacing for labour and birth.

The influence of mycophenolate mofetil versus azathioprine and mycophenolic acid pharmacokinetics on the incidence of acute rejection and infectious complications after renal transplantation

PURPOSE

The present retrospective study investigated the influence of mycophenolate mofetil (MMF) instead of azathioprine (AZA) as part of tacrolimus-based immunosuppression. Mycophenolic acid (MPA) pharmacokinetic (PK) parameters were used for associations with the incidence of acute rejection (AR) episodes and infectious complications after renal transplantation.

METHODS

The 66 consecutive renal transplant recipients reported herein excluded ABO-incompatible transplants or cytomegalovirus (CMV)-seronegative recipients. The immunosuppressive regimen consisted of tacrolimus, steroids, and AZA 1-2 mg/kg/d in 22 patients (between February 1998 and December 2000) or MMF 2 g/d in 44 patients (since January 2001). CMV infection was defined as positive CMV-antigenemia. MPA PK was studied on day 28 after transplantation in 21 recipients.

RESULTS

AR occurred in 13.6% of patients in the MMF group compared with 18.2% in the AZA group. The viral infection (CMV, varicella zoster virus, adenovirus hemorrhagic cystitis, and malignancy related to Epstein-Barr [EB] virus) rate was 22.7% in the MMF group and 0% in the AZA group (P = .015). There were no bacterial or fungal infections observed in the 2 groups. MMF dose per body weight was significantly lower among patients with AR than those without AR (25.1 vs 35.6 mg/kg; P = .026). There were no differences in MPA PK parameters between patients with and without viral infections.

CONCLUSIONS

Patients treated with MMF required less treatment for AR, however, there were no significant differences. MMF dose per body weight may play an important role in the occurrence of AR. Although virus infections occurred in recipients treated with MMF, MPA PK did not influence the infectious complications after renal transplantation.

Impact of CYP3A5 and MDR1(ABCB1) C3435T polymorphisms on the pharmacokinetics of tacrolimus in renal transplant recipients

OBJECTIVE

The objective of this study was to assess the influence of CYP3A5 and MDR1 genetic polymorphisms on tacrolimus pharmacokinetics in Japanese renal transplant recipients.

METHOD

The pharmacokinetic parameters of tacrolimus were calculated in steady-state on day 28 after transplantation. Polymerase chain reaction-restriction fragment length polymorphism and direct sequence methods were used for CYP3A5 and MDR1 polymorphisms, respectively.

RESULTS

The dose-adjusted area under the concentration-time curve (AUC0-12) was significantly lower among CYP3A5*1 carriers than those bearing CYP3A5*3/*3. (0.570 +/- 0.105 vs 0.865 +/- 0.343 ng.h/mL per mg/kg, P = .00322). The daily tacrolimus dose per body weight was significantly higher in CYP3A5*1 carriers than those of CYP3A5*3/*3 carriers (0.271 +/- 0.110 vs 0.150 +/- 0.056 mg/kg, P = .00016). In this study, a distinction was made between carriers of CYP3A5*1/*1+*1/*3 and CYP3A5*3/*3 to investigate the influence of the MDR1 C3435T mutation on tacrolimus pharmacokinetics. The MDR1 C3435T polymorphisms did not affect any tacrolimus pharmacokinetic parameter in either group.

CONCLUSIONS

Renal transplant recipients who were CYP3A5*1 carriers required a higher dose of tacrolimus than CYP3A5*3/*3, indicating a significantly lower dose-adjusted AUC0-12 of tacrolimus. In contrast, MDR1 C3435T polymorphism was not an important factor in tacrolimus pharmacokinetics.

Arundic acid (ONO-2506) ameliorates delayed ischemic brain damage by preventing astrocytic overproduction of S100B

After focal cerebral ischemia, the infarct volume increases rapidly within acute infarct expansion (initial 12 to 24 h) and continues slowly during delayed infarct expansion (25 to 168 h). While acute infarct expansion represents progressive necrosis within the ischemic core, delayed infarct expansion starts as disseminated apoptotic cell death in a narrow rim surrounding the infarct border, which gradually coalesces to form a larger infarct. Discovery of a distinct correlation between reactive astrogliosis along the infarct border and delayed infarct expansion in the rodent ischemia model led us to investigate the possible causal relationship between the two events. Specifically, the calcium binding protein S100B exerts detrimental effects on cell survival through activation of various intracellular signaling pathways, resulting in altered protein expression. Arundic acid [(R)-(-)-2-propyloctanoic acid, ONO-2506] is a novel agent that inhibits S100B synthesis in cultured astrocytes. In the rodent ischemia model, this agent was shown to inhibit both the astrocytic overexpression of S100B and the subsequent activation of signaling pathways in the peri-infarct area. Concurrently, delayed infarct expansion was prevented, and neurologic deficits were promptly ameliorated. The results of subsequent studies suggest that the efficacy of arundic acid is mediated by restoring the activity of astroglial glutamate transporters via enhanced genetic expression.

Incidence and Risk Factors of Clinical Characteristics, Tacrolimus Pharmacokinetics, and Related Genomic Polymorphisms for Posttransplant Diabetes Mellitus in the Early Stage of Renal Transplant Recipients

PURPOSE

Posttransplant diabetes mellitus (PTDM) is an important complication in a tacrolimus (TAC)-based immunosuppressive regimen. The present study investigated the incidence, clinical risk factors, TAC pharmacokinetics (PK), and genomic polymorphisms related to TAC-PK or diabetes mellitus (DM) under the TAC-based immunosuppressive protocol.

PATIENTS AND METHODS

Seventy-one nondiabetic renal allograft recipients transplanted from February 1998 to March 2004 were studied. Patients with over 6.5 mg/dL of hemoglobin A1c on sequential blood samples or requiring insulin or oral antidiabetic agents around 6 months after transplantation were diagnosed as having PTDM.

RESULTS

Six months after transplantation, 10 recipients (14.1%) developed PTDM. The positive risk factors were age (P = .003) and body mass index (P = .035). There were no significant differences in gender distribution, pretransplant dialysis period, dialysis modality, acute rejection rate, total steroid doses, TAC-PK, or its related genomic polymorphisms between the two groups. In the DM-related polymorphisms, the frequency of PTDM was significant higher in patients with the VDR TaqI tt or Tt genotype than in those with the TT genotype (P = .013). After a multivariate analysis, age over 50 years (P = .007, odds ratio 8.92) and the presence of VDR TaqI t allele (P = .043, odds ratio 6.71) were correlated with the development of PTDM.

CONCLUSION

The incidence of PTDM in our series was 14.1%. Age over 50 years was a risk factor. The presence of VDR TaqI t allele might be a risk for PTDM. An association between TAC-PK and development of PTDM was not observed.

Favourable association of leg fat with cardiovascular risk factors

OBJECTIVES

To assess the association of trunk and leg fat mass (FM) and leg lean tissue mass (LTM) with conventional cardiovascular risk factors.

DESIGN

Cross-sectional study.

SETTING AND SUBJECTS

We studied 1249 men and 3007 women (age 20-79 years) who attended a research institute for a health checkup between October 1995 and February 2004.

MAIN OUTCOME MEASURES

Body mass index, waist circumference (WC), hip circumference (HC), systolic and diastolic blood pressure, total cholesterol, HDL cholesterol, triglycerides, glucose and haemoglobin A(1C) were measured. Trunk FM, leg FM and leg LTM were obtained by dual-energy X-ray absorptiometry. We evaluated the associations between the indices for regional body composition and cardiovascular risk factors, which included hypertension, hypercholesterolaemia, hypo-HDL cholesterolaemia, hypertriglyceridaemia, dyslipidaemia and diabetes mellitus.

RESULTS

Increase in WC and HC respectively showed increase and decrease in odds ratios of cardiovascular risk factors. Increase in trunk FM by 1 kg significantly increased the risk of the cardiovascular risk factors with the odds ratios ranging between 1.11 and 1.45. Increase in leg FM by 1 kg significantly decreased the risk with the odds ratios ranging between 0.52 and 0.90, except for the nonsignificant results for hypercholesterolaemia and hypo-HDL cholesterolaemia in men. Odds ratios of 1 kg increase in leg LTM were only significant for dyslipidaemia in men and hypercholesterolaemia in women (both 0.93).

CONCLUSIONS

WC and HC showed opposite and independent associations with cardiovascular risk factors. The favourable association of HC was mainly attributable to that of leg FM.

Immune responses in rainbow trout Oncorhynchus mykiss induced by a potential probiotic bacteria Lactobacillus rhamnosus JCM 1136

This study was undertaken to examine the effect of supplementing a suggested probiotic bacteria Lactobacillus rhamnosus JCM 1136 in feed on immune response and gut flora composition of rainbow trout Oncorhynchus mykiss. The probiotic bacteria were incorporated into a commercial feed to constitute two experimental diets containing either 10(9) or 10(11) colony forming unit of live bacteria/g of feed while a third diet without the bacterial supplement served as the control diet. The diets were offered to rainbow trout (75g average weight) in triplicate tanks for 30 days. Fish were sampled at 10, 20 and 30 days after commencement of the feeding trial to determine the proportion of the given probiont in the gut microflora composition and the nonspecific humoral and cellular immune responses on the 30th day. The relative proportion of the probiont increased with the feeding duration in the intestine, but not in the stomach. The proportion of L. rhamnosus in the stomach corresponded to the intake levels while no such relation existed in the intestine. The serum lysozyme and complement activities were significantly greater in fish fed the higher level of probiont compared with the control fish. The phagocytic activity of head kidney leucocytes also showed similar tendencies. These observations indicate the potential immuno-regulatory role of probiotic organisms in rainbow trout.

[Thoracoscopic surgery using a new bronchial blocker]

We report use of a new bronchial blocker through a single-lumen endotracheal tube to achieve one-lung ventilation to perform thoracoscopic operation in patients in whom placement of the double-lumen tube failed and difficult intubation is predicted. The bronchial blocker tube was placed into the aimed bronchus under the bronchoscopic vision and the cuff of the blocker was inflated to achieve one-lung ventilation. In all of the 4 patients, the bronchial blocker could be inserted and placed safely, quickly, and exactly under the fiberoptic flexible bronchoscopic vision to perform thoracoscopic operation without any complications. The new bronchial blocker tube through the indwelling endotracheal tube may have advantages in situations where placement of double-lumen endotracheal tubes is technically impossible or inappropriate. The use of the new bronchial blocker tube will, however, require careful evaluation in larger series.

[Thoracoscopic pericardial resections for malignant pericardial effusions]

We have performed 5 thoracoscopic pericardial resections for malignant pericardial effusions. An initial trocar was placed in the seventh or eighth intercostal space posterior to the midaxillary line. Two additional trocars were placed, usually in the sixth intercostals spaces in the anterior axillary and posterior axillary lines. Using an endoscopic grasping instrument and scissors through the working ports, a pericardial resection was performed. All patients were successfully managed by thoracoscopic pericardial resections. Two of the 5 patients had associated malignant pleural effusions that were able to be managed at the same time by thoracoscopy. The average chest tube duration was 1.8 days. There has been no reaccumulation of pericardial effusions in all patients at an average follow-up of 5 months. The thoracoscopic approach could be minimally invasive and the procedure of choice in performing pericardial resections in selected patients with malignant pericardial effusions who are expected to have a reasonable life expectancy.

Enhancement of innate immunity in rainbow trout (Oncorhynchus mykiss Walbaum) associated with dietary intake of carotenoids from natural products

The effects of orally administered carotenoids from natural sources on the non-specific defense mechanisms of rainbow trout were evaluated in a nine-week feeding trial. Fish were fed four diets containing either beta-carotene or astaxanthin at 100 and 200 mg kg-1 from the marine algae Dunaliella salina and red yeast Phaffia rhodozyma, respectively, and a control diet containing no supplemented carotenoids. Specific growth rate and feed:gain ratio were not affected by dietary carotenoid supplementation. Among the humoral factors, serum alternative complement activity increased significantly in all carotenoid supplemented groups when compared to the control. On the other hand, serum lysozyme activity increased in the Dunaliella group but not in the Phaffia group, whereas plasma total immunoglobulin levels were not altered by the feeding treatments. As for the cellular responses, the superoxide anion production from the head kidney remained unchanged while the phagocytic rate and index in all supplemented groups were significantly higher than those of the control. These findings demonstrate that dietary carotenoids from both D. salina and P. rhodozyma can modulate some of the innate defense mechanisms in rainbow trout.

Domain structures of chlorophyllide a oxygenase of green plants and Prochlorothrix hollandica in relation to catalytic functions

Chlorophyll b is a photosynthetic antenna pigment found in prochlorophytes and chlorophytes. In chlorophytes, its biosynthesis regulates the photosynthetic antenna size. Chlorophyll b is synthesized from chlorophyll a in a two-step oxygenation reaction by chlorophyllide a oxygenase (CAO). In this study, we first identified the entire sequence of a prochlorophyte CAO gene from Prochlorothrix hollandica to compare it with those from chlorophytes, and we examined the catalytic activity of the gene product. Southern blot analysis showed that the CAO gene is presented in one copy in the P. hollandica genome. The P. hollandica CAO gene (PhCAO) has a coding capacity for 367 amino acids, which is much smaller than that of Arabidopsis thaliana (537 amino acids) and Oryza sativa (542 amino acids) CAO genes. In spite of the small size, PhCAO catalyzed the formation of chlorophyll b. By comparing these sequences, we classified the land-plant sequences into four parts: the N-terminal sequence predicted to be a transit peptide, the successive conserved sequence unique in land plants (A-domain, 134 amino acids), a less-conserved sequence (B-domain, 30 amino acids) and the C-terminal conserved sequence common in chlorophytes and prochlorophytes (C-domain, 337 to 344 amino acids). We demonstrated that the C-domain is sufficient for catalytic activity by transforming the cyanobacterium Synechocystis sp. PCC6803 with the C-domain from A. thaliana. In this paper, the role of the A-domain is discussed in relation to the formation of light-harvesting chlorophyll a/b-protein complexes in land plants.

Effect of FK506 eye drops on late and delayed-type responses in ocular allergy models

BACKGROUND

It is well-known that FK506 strongly inhibits cytokine production by T cells in vitro. However, less evidence is available from in vivo studies of ocular allergy.

OBJECTIVE

To study the anti-inflammatory effect of FK506 eye drops on late and delayed-type responses in several animal models of ocular allergy.

METHODS

Rats and guinea-pigs were sensitized with egg albumin (EA) in adjuvant and later challenged by topical EA application to their eyes to examine the late response. Biopsy specimens of conjunctiva were stained with haematoxylin-eosin or stained for T cells and eosinophils. In addition, rats, rabbits and guinea-pigs were sensitized with complete Freund's adjuvant and later challenged by injecting purified protein derivatives for the delayed-type response. Bulbar conjunctival oedema and hyperaemia were graded by score in rabbits, and Evans blue (EB) extravasation was measured in rats and guinea-pigs. FK506 (0.01-1%) and steroid (0.1%) eye drops were instilled in the eyes of animals several times, before and after challenge.

RESULTS

FK506 eye drops inhibited T cell and eosinophil infiltration in the late response and EB extravasation in the delayed-type response in rats. Also, they inhibited conjunctival oedema, hyperaemia and ocular mucus in the delayed-type response in rabbits. These effects were similar to those of steroid eye drops (betamethasone sodium phosphate, fluorometholone). FK506 eye drops also inhibited inflammatory cell infiltration, the loss of conjunctival epithelium and decrease of goblet cells in the late response as well as EB extravasation in the delayed-type response in guineapigs, a steroid-resistant species.

CONCLUSION

FK506 eye drops inhibit late and delayed-type responses in animal models of ocular allergy.

Nonspecific immune response of rainbow trout (Oncorhynchus mykiss Walbaum) in relation to different status of vitamin E and highly unsaturated fatty acids

This study was designed to examine the effects of dietary vitamin E (VE) on modulation of immune responses when supplied with two levels of n-3 highly unsaturated fatty acids (n-3 HUFA) in rainbow trout, Oncorhynchus mykiss. Six semipurified diets were prepared containing three levels of dietary VE (0, 100 or 1000 mg alpha-tocopheryl acetate kg(-1) diet) and n-3 HUFA either at 20 or 48% of dietary lipid provided from fish oil or docosahexaenoic acid (DHA) concentrated fish oil respectively. The diets were fed to rainbow trout (100 g initial mean weight) for 15 weeks. The VE, vitamin C (VC) content in plasma and tissues and the nonspecific immune responses, both humoral (alternative complement activity, total immunoglobulin) and cellular (phagocytosis, nonspecific cytotoxicity) were examined. VE contents in the kidney reflected the dietary input but were lower in fish fed 48% n-3 HUFA diets, and could have impaired some of immune responses compared to fish fed 20% n-3 HUFA. VC contents in kidney followed the same pattern as VE. Both humoral and cellular immune functions deteriorated in fish fed VE deficient diets whereas improvement in most of the parameters corresponded to its supplementation. However, the higher dose of dietary VE did not substantially enhance the responses assayed compared to the 100 mg dose. Besides clearly indicating the role of VE in maintaining the immune functions in fish in relation to dietary n-3 HUFA, this study has revealed that optimum health benefits could be achieved when VE is maintained slightly above the levels generally recommended for normal growth.

Effect of zaprinast on nitric oxide levels in serum and aortic tissue

Nitric oxide (NO), which is synthesized from the guanidino nitrogen of l-arginine by nitric oxide synthase (NOS), plays an important role in many physiological and pathological processes. Most of the effects of NO are mediated by cyclic guanosine 3'5 monophosphate (cGMP), which is synthesized by soluble guanylate cyclase (sGC) and degraded by phosphodiesterases (PDEs). Although the NO/cGMP pathway has been extensively studied, remarkably little is known about the regulation of NO release. Furthermore, controversial studies have indicated that intervention of the sGC/cGMP pathway modulates the release of NO. The purpose of this study was to evaluate the hypothesis that drugs that affect the sGC/cGMP pathway may modulate NO release and, if so, is there a correlation between NO levels and blood pressure effect? To this end, we investigated the effects of the PDE 5 inhibitor zaprinast on mean arterial pressure (MAP), nitrite/nitrate levels and cGMP in normotensive male Sprague Dawley rats. The results of the current study indicated that zaprinast dose-dependently increased plasma cGMP levels at 18, 24 and 36 mg/kg and decreased MAP at 24 and 36 mg/kg. However, zaprinast at 18, 24 and 36 mg/kg did not affect NO levels either in serum or aortic tissue. We have concluded that the PDE 5 inhibitor zaprinast has no regulatory effect on NO release in serum and aortic tissue, and NO was not involved in the hypotensive effect of zaprinast.

Basal Membrane Localization of MRP1 in Human Placental Trophoblast

The placental trophoblast is considered to act as a barrier between mother and fetus, mediating the exchange of various materials across the placenta. ATP-binding cassette (ABC) transporters such as P-glycoprotein (P-gp) and multidrug-resistance protein (MRP) are expressed in the placenta and function as efflux transport systems for xenobiotics. In the present study, we aimed to determine the localization of MRP1 in the human placenta in comparison with that of P-gp. Western blotting analysis with human placental membrane vesicles indicated that P-gp and MRP1 are localized on the brush-border membranes and basal membranes, respectively. Immunohistochemical analysis with human normal full-term placenta showed that anti-P-gp monoclonal antibody F4 stained the brush-border side of the trophoblast cells, whereas anti-MRP1 monoclonal antibody MRPr1 stained the basal side. These results confirm that P-gp and MRP1 are located on the brush-border membranes and basal membranes, respectively, of human full-term placental trophoblast. MRP1 was also detected on the abluminal side of blood vessels in the villi. Accordingly, MRP1 may play a role distinct from that of P-gp, which is considered to restrict the influx of xenobiotics into the fetus.