Adoptive immunotherapy to lower postsurgical recurrence rates of hepatocellular carcinoma: a randomised trial

BACKGROUND

Postsurgical recurrence of hepatocellular carcinoma (HCC) is frequent and fatal. Adoptive immunotherapy is active against HCC. We assessed whether postoperative immunotherapy could lower the frequency of recurrence.

METHODS

Between 1992 and 1995, we did a randomised trial in which 150 patients who had undergone curative resection for HCC were assigned adoptive immunotherapy (n=76) or no adjuvant treatment (n=74). Autologous lymphocytes activated vitro with recombinant interleukin-2 and antibody to CD3 were infused five times during the first 6 months. Primary endpoints were time to first recurrence and recurrence-free survival and analyses were by intention to treat.

FINDINGS

76 patients received 370 (97%) of 380 scheduled lymphocyte infusions (mean cell number per patient 7.1x10(10) [SD 2.1]; CD3 and HLA-DR cells 78% [16]), and none had grade 3 or 4 adverse events. After a median follow-up of 4.4 years (range 0.2-6.7), adoptive immunotherapy decreased the frequency of recurrence by 18% compared with controls (45 [59%] vs 57 [77%]) [corrected] patients. Time to first recurrence in the immunotherapy group was significantly longer than that in the control group (48% [37-59] vs 33% [22-43] at 3 years, 38% [22-54] vs 22% [11-34] at 5 years; p=0.008). The immunotherapy group had significantly longer recurrence-free survival (p=0.01) and disease-specific survival (p=0.04) than the control group. Overall survival did not differ significantly between groups (p=0.09).

INTERPRETATION

Adoptive immunotherapy is a safe, feasible treatment that can lower recurrence and improve recurrence-free outcomes after surgery for HCC.

A new tracheal bioartificial organ: evaluation of a tracheal allograft with minimal antigenicity after treatment by detergent

The aim of this study was to reduce the antigenicity of tracheal allografts by detergent treatment. We attempted to apply these grafts to tracheal immunosuppressant-free allotransplantation. Fresh tracheal grafts were harvested from donor beagle dogs and treated with a detergent at 4 degrees C for 48 hours. By using treated grafts, we have performed tracheal immunosuppressant-free transplantation in six dogs at an intrathoracic five-ring defect. Implanted grafts were covered with an omental pedicle. In five of the six grafts, complete removal of the epithelium and mixed glands was recognized with both light microscopy and scanning electron microscopy. The appearance of the cartilage cells in the grafts was similar to those in fresh trachea. Five dogs that received detergent treated grafts survived uneventfully. The grafts had been incorporated by the host trachea without stenosis. On the one tracheal graft in which removal of the epithelium was incomplete (noted after implantation), moderate stenosis occurred 1 month after placement. These results suggest that removal of the tracheal epithelium and mixed glands can remarkably reduce tracheal antigenicity. A tracheal graft that has its epithelium and mixed glands removed can be used in tracheal immunosuppressant-free allotransplantation.

Rat multispecific organic anion transporter 1 (rOAT1) transports zidovudine, acyclovir, and other antiviral nucleoside analogs

Organic anion transporter 1 (OAT1) is a p-aminohippurate/dicarboxylate exchanger that plays a primary role in the tubular secretion of endogenous and exogenous organic anions. OAT1 is located in the basolateral membrane of the proximal tubular cells and mediates the uptake of various organic anions from the peritubular fluid. In this study, we investigated the transport of antiviral nucleoside analogs via rat OAT1 (rOAT1) using a heterologous expression system in Xenopus laevis oocytes. Oocytes injected with rOAT1 cRNA showed significantly higher uptake of zidovudine (AZT) and acyclovir (ACV) than control oocytes. rOAT1-mediated uptake of AZT and ACV was probenecid-sensitive and increased by the outwardly directed gradient of glutarate. The affinity of rOAT1 for AZT and ACV was determined to be 68 and 242 microM, respectively. Five other antiviral agents that we studied (zalcitabine, didanosine, lamivudine, stavudine, and trifluridine) were also shown to be transported by rOAT1, whereas foscarnet, a phosphate analog, was not. The aforementioned nucleoside analogs lack a typical anionic group and are not very hydrophobic. This study demonstrates extension of the substrate spectrum of rOAT1 and provides a molecular basis for the pharmacokinetics of antiviral nucleoside analogs.

Impaired interleukin-2 production in T-cells from a patient with Wiskott-Aldrich syndrome: basis of clinical effect of interleukin-2 replacement therapy

Interleukin-2 production may be one of the underlying causes of Wiskott-Aldrich syndrome immunodeficiency and recombinant interleukin-2 administration (or an infusion of T-cells expanded by CD3 stimulation and rIL-2) is able, to some extent, to restore defective T-cell function.

Detection of tumor cells in blood using CD45 magnetic cell separation followed by nested mutant allele-specific amplification of p53 and K-ras genes in patients with colorectal cancer

A new method for detecting circulating tumor cells that is based on magnetic-activated cell separation (MACS) and nested mutant allele-specific amplification (nested MASA) was evaluated in patients with colorectal cancer using the p53 and K-ras genes as genetic markers. By negative selection with anti-CD45 monoclonal antibody-conjugated supermagnetic microbeads, the proportion of tumor cells was enriched 9-fold. By the combination of MACS and nested MASA, 10 tumor cells in 10(7) normal peripheral blood mononuclear cells could be detected without false-positives. Using this method, we examined blood taken from the tumor drainage veins of 23 patients with colorectal cancer. Eighty-seven percent (20/23) of primary tumor tissues showed p53 and/or K-ras gene mutations. Forty-five percent (9/20) of patients with p53 and/or K-ras mutations in the primary tumor showed the same mutated genes in the blood samples. There was a significant association between the presence of p53 and K-ras gene mutation in the blood and tumor size, depth of invasion, and venous invasion. Blood gene mutation was detected in 80% (4/5) of samples from patients with synchronous liver metastases. Sixty percent (3/5) of patients with mutant genes in the blood developed asynchronous liver metastases after surgery. The overall survival of patients with p53 and/or K-ras gene mutation-positive findings in blood was significantly shorter than that of patients testing negative on Kaplan-Meier analysis. Our results suggest that the method may be useful for reliable detection of tumor cells circulating in the blood and may help to identify patients at high risk for relapse.

Use of a newly developed artificial nerve conduit to assist peripheral nerve regeneration across a long gap in dogs

There is now considerable evidence that peripheral nerves have the potential to regenerate if an appropriate microenvironment is provided. However, there are only a few reports of the successful use of artificial nerve conduits to repair major nerve defects more than 30 mm in length. In this study, we examined nerve regeneration across a long gap in the dog peroneal nerve using a novel artificial nerve conduit developed by our group. The conduit consists of a polyglycolic acid (PGA) collagen tube filled with laminin coated collagen fibers. In 12 dogs, the nerve conduit was implanted across an 80 mm gap in the left peroneal nerve. Three months after surgery, compound muscle action potentials (CMAPs) and somatosensory evoked potentials (SEPs) were detected. Evaluation of locomotor function revealed obvious limping for up to 3 months, but no marked difficulty in walking by 6 months. Microscopic observation of the regenerated nerve segment at 12 months showed numerous myelinated nerve fibers, which were smaller in diameter and enclosed in a thinner myelin sheath than normal axons. These results suggest that our artificial nerve conduit has potential usefulness in enhancing peripheral nerve regeneration, even across large gaps.

Collagen coated Y-shaped prosthesis for carinal replacement promotes regeneration of the tracheal epithelium

Carinal reconstruction has the highest operative mortality rate in pulmonary surgery, and high tension at the anastomoses is one of the reasons. We have reported previously that a new Y-shaped artificial trachea gives acceptable short-term results. Here, we report our long-term observations and histologic findings. A Y-shaped Marlex mesh tube reinforced by a polypropylene spiral was coated with collagen, which was extracted from porcine skin, to increase the biocompatibility and airtightness of the prosthesis. Replacement of the carina was performed in 20 beagle dogs. The prosthesis was covered by the omental pedicle in all dogs. Six of the 20 dogs survived past 6 months, and 4 were in good condition when they were killed. The other 13 dogs died within 11 days of the operation. The main cause of death was air leakage from the prosthesis. Bronchoscopic examination of the surviving dogs 12 months after surgery revealed that the prosthesis was covered with regenerated tissue, and neither stenosis nor dehiscence was recognized; 15 months after implantation microscopic examination showed the growth of ciliated epithelial cells over the lumen of the prosthesis. These results suggest that our Y-shaped artificial trachea might be useful for reconstruction of the carina with tissue regrowth, although some improvement of the prosthesis is necessary.

Immunosuppressant-free allotransplantation of the trachea: the antigenicity of tracheal grafts can be reduced by removing the epithelium and mixed glands from the graft by detergent treatment

OBJECTIVE

To develop a method for eliminating the epithelium and mixed glands from tracheal grafts by detergent treatment and evaluate these grafts for immunosuppressant-free allotransplantation in dogs.

METHODS

Fresh canine tracheal grafts were treated with a detergent (1% Triton X-100 t-octylphenoxypolyethoxyethanol; T-9284; Sigma Chemical Co, St Louis, Mo) at 4 degrees C for 48 hours. The grafts were then used for intrathoracic 5-ring tracheal replacement in other dogs without immunosuppressant treatment (n = 6, detergent treatment group). In the control group (n = 6) fresh untreated canine tracheal segments were implanted as allografts. All the implanted grafts were covered with an omental pedicle.

RESULTS

In the detergent treatment group the chondrocytes in the graft had a similar appearance to those in the fresh trachea, indicating that the chondrocytes remained viable after the detergent treatment. In 5 of the 6 grafts, the epithelium and mixed glands had been removed completely. After transplantation, these 5 grafts were incorporated by the host trachea without stenosis. In the remaining treated tracheal graft, in which removal of the epithelium was incomplete, moderate stenosis was observed at the fourth week after implantation, although this was not progressive. In the control group, granulation tissue of the graft and significant stenosis were observed after transplantation.

CONCLUSION

The antigenicity of tracheal grafts can be greatly reduced by removing the epithelium and mixed glands by the use of detergent treatment. The epithelium and mixed glands of the graft appear to be the determining elements involved in rejection after tracheal allotransplantation.

The multispecific organic anion transporter (OAT) family

Organic anion transporters play important roles in the elimination of a variety of endogenous substances, xenobiotics and their metabolites from the body. During the last decade, molecular cloning has identified several families of multispecific organic anion transporters mediating the renal and hepatic elimination of organic anions and, most recently, the OAT (organic anion transporter) family, the founding member of which (OAT1) is the basolateral p-aminohippurate (PAH) transporter in the renal proximal tubule. So far, four isoforms have been identified. OATs are membrane proteins with 12 putative membrane-spanning domains and function as sodium-independent exchangers or facilitators. OATs show weak structural similarity to organic cation transporters (OCTs) and OCTN/carnitine transporters. OATs are multispecific organic anion transporters, the substrates of which include both endogenous (e.g. cyclic nucleotides, prostaglandins, urate, dicarboxylates) and exogenous anions (various anionic drugs and environmental substances). All members of the OAT family are expressed in the kidney, while some are also expressed in the liver, brain and placenta. The OAT family represents the renal secretory pathway for organic anions and is also involved in the distribution of organic anions in the body.

Peripheral nerve regeneration across an 80-mm gap bridged by a polyglycolic acid (PGA)-collagen tube filled with laminin-coated collagen fibers: a histological and electrophysiological evaluation of regenerated nerves

We evaluated peripheral nerve regeneration across an 80-mm gap using a novel artificial nerve conduit. The conduit was made of a polyglycolic acid (PGA)-collagen tube filled with laminin-coated collagen fibers. Twelve beagle dogs underwent implantation of the nerve conduit across an 80-mm gap in the left peroneal nerve. In four other dogs used as negative controls, the nerve was resected and left unconnected. Histological observation showed that numerous unmyelinated and myelinated nerve fibers, all smaller in diameter and with a thinner myelin sheath than normal nerve fibers, regrew through and beyond the gap 12 months after implantation. The distribution of the regenerated axonal diameters was different from that of the normal axonal diameters. Compound muscle action potentials, motor evoked potentials, and somatosensory evoked potentials were recorded in most animals 3 months after implantation. Peak amplitudes and latencies recovered gradually, which indicating the functional establishment of the nerve connection with the target organs. In addition to the ordinary electrophysiological recoveries, potentials with distinct latencies originating from Aalpha, Adelta and C fibers became distinguishable at the 6th lumbar vertebra following stimulation of the peroneal nerve distal to the gap 12 months after implantation. The pattern of walking without load was restored to almost normal 10-12 months after implantation. Neither electrophysiological nor histological restoration was obtained in the controls. Our nerve conduit can guide peripheral nerve elongation and lead to favorable functional recovery across a wider nerve gap than previously reported artificial nerve conduits.

Experimental carinal replacement with an Y-shaped collagen-conjugated prosthesis

BACKGROUND

A new prosthesis was designed for reconstruction of the bifurcation of the trachea and used for experimental carinal replacement in dogs.

METHODS

The main Frame of the new prosthesis consists of Y-shaped Marlex mesh tube reinforced with polypropylene spirals. It is coated with collagen extracted from porcine skin to provide biocompatibility and airtightness. Carinal replacement with omentopexy was performed in 17 dogs.

RESULTS

Seven dogs survived the postoperative period, and 10 dogs died within 11 days after the operation. The main causes of early postoperative death were fistula and air leakage from the prosthesis. Causes of late postoperative death were obstruction of the main bronchus (two) and lung abscess (one). The four long-term survivors had no stenosis or dehiscence until they were sacrificed 15 months after the operation. Histological examination of these dogs revealed that the luminal surface was covered either with ciliated columnar epithelium or non-ciliated squamous epithelium.

CONCLUSIONS

The study results suggest the possibility of successful prosthetic carinal reconstruction with epithelial regrowth using this Y-shaped prosthesis.

Carinal reconstruction with a Y-shaped collagen-conjugated prosthesis

BACKGROUND

Carinal reconstruction by direct suturing is associated with a high mortality because high tension at the anastomosis can lead to tracheobronchial fistula. A new tracheal prosthesis was therefore designed for reconstruction of the tracheal bifurcation and applied for experimental carinal replacement in dogs.

METHODS

The main frame of the new prosthesis consists of a Y-shaped Marlex mesh tube (C.R. Bard, Inc, Billerica, Mass) reinforced with polypropylene spirals, to which collagen extracted from porcine skin is chemically conjugated to provide biocompatibility and airtightness. This conjugated collagen is composed of amorphous and sponge collagen layers. The tracheobronchial bifurcation was replaced with the prosthesis in 10 beagle dogs.

RESULTS

Eight dogs survived the postoperative period, and 2 dogs died within 4 days after the operation. Bronchoscopic examination revealed that the tracheal prosthesis was covered with smooth whitish tissue and that no stenosis or dehiscence was present in the 8 dogs even 6 months after the operation. Slight mesh exposure was recognized in 1 dog. Histologic examination revealed that approximately one half of the luminal surface was covered with ciliated columnar epithelium or nonciliated squamous epithelium. In the remaining lumen, especially in the middle portion of the prosthesis, connective tissue without epithelium was observed.

CONCLUSIONS

These long-term results indicate that our bifurcated tracheal prosthesis can be used for reconstruction of the tracheobronchial bifurcation with long-term safety.

Six-year disease-free survival of a patient with metastatic eyelid squamous cell carcinoma and colon adenocarcinoma after repeated postoperative adoptive immunotherapy

A 74-year-old male was affected concurrently with squamous cell carcinoma of the left eyelid and adenocarcinoma of the colon, both with lymph node metastasis. He underwent exenteration of the left orbit with left modified radical neck dissection and subsequently resection of the transverse colon with regional lymph node dissection. The patient has been treated by an adoptive immunotherapy as a sole postoperative modality without receiving any chemotherapeutic agents causing immunosuppression. For the adoptive immunotherapy, autologous peripheral blood lymphocytes were activated with an immobilized anti-CD3 antibody and IL-2 for 14 days (the CD3-AT cells). The infusion with 1.38 x 10(10) CD3-AT cells has been repeated 150 times in total at the time of writing. Neither recurrence nor additional metastasis has been detected for 6 years after surgery.

Single-Microparticle Injection and Microabsorptiometry: Direct Analysis of Sorption Processes

Sorption processes of methylene blue in a single silica gel microparticle in an aqueous solution was kinetically analyzed by a new technique combined with the microcapillary injection/manipulation and microabsorptiometry of the single particle. The observed sorption rates were analyzed in terms of the solute concentration in water and the particle size. The sorption processes were governed by diffusion of the solute in the particle. Copyright 2000 Academic Press.

Developmental changes in multispecific organic anion transporter 1 expression in the rat kidney

BACKGROUND

The cDNA of the multispecific organic anion transporter 1 (OAT1) responsible for the tubular secretion of organic anions was recently isolated. In the current study, we investigated the developmental changes in OAT1 expression in the rat kidney.

METHODS

Ontogenic expression of rat OAT1 was investigated by Northern blot, in situ hybridization, Western blot, and immunohistochemical analysis. In addition, para-aminohippurate (PAH) accumulation was measured using fetal, neonatal, and adult rat kidney slices.

RESULTS

In Northern blot analysis, OAT1 was detected as early as on embryonic day 18 in the fetal kidney. The expression level of OAT1 mRNA increased remarkably just after birth (postnatal day 0). In situ hybridization revealed OAT1 expression on embryonic day 19. In both the fetal and neonatal kidneys, OAT1 mRNA was localized in a relatively deep region in the cortex. Western blot analysis detected OAT1 protein on embryonic day 20, and the expression level increased after birth. Immunohistochemical analysis did not reveal OAT1 staining in the fetal kidneys. A faint signal of OAT1 protein was detected on postnatal day 0; thereafter, the expression level increased. In the functional study using kidney slices, low but definite probenecid-sensitive PAH accumulation was noted in fetal rat kidney on embryonic day 20. After birth, probenecid-sensitive PAH uptake was increased.

CONCLUSIONS

The present study consistently demonstrates the remarkable increase of OAT1 expression after birth, and the immature excretory capacity of the proximal tubules of the neonatal kidney can be attributed, at least in part, to the low expression level of OAT1.

Accumulation of identical T cell clones in the right and left lobes of the thyroid gland in patients with Graves' disease: analysis of T cell clonotype in vivo

To elucidate the involvement of intrathyroidal T cells in the thyroid antigen-specific immune response in Graves' disease (GD), we investigated whether identical T cell clonotypes accumulate clonally in the right and left lobes of thyroid glands of GD patients. mRNAs extracted from thyroid glands of five females patients with GD were reverse-transcribed to cDNA and then the genes coding the T cell receptor B chain variable (V-NDN-J) region were amplified using polymerase chain reaction. Single strand conformation polymorphism analysis and subsequently nucleotide sequencing were also performed to determine the clonotype of accumulating T cells. T cells infiltrating the thyroid glands showed oligoclonal expansion. The expanded T cell clonotypes were not detected in peripheral blood of the same patients. Importantly, the majority of expanding T cell clonotypes in the two lobes of the thyroid glands were identical. Our findings suggest that the clonal expansion of identical T cell clonotypes in the two lobes is driven by factors common to both lobes, such as thyroid-specific antigens, in patients with Graves' disease.

Purinoceptor-mediated calcium mobilization and cellular proliferation in cultured bovine corneal endothelial cells

In the present study, we investigated the effect of adenosine triphosphate (ATP) on cytosolic free calcium mobilization and mitogenic activity in cultured bovine corneal endothelial cells (BCEC). The [Ca2+]i was determined using a Ca2+ sensitive indicator, Fura-2/AM, and cell proliferation was evaluated by counting the cell number. ATP, its metabolites and analogs caused transient increase in [Ca2+]i in a concentration-dependent manner (10(-7) M-10(-3) M) and the potency of agonists was ordered as follows: 2-methylthio-ATP > uridine triphosphate > ATP > adenosine diphosphate. Adenosine monophosphate and adenosine did not affect [Ca2+]i. ATP (10(-4) M) also promoted the accumulation of inositol trisphosphate (IP3). The ATP-induced transient [Ca2+]i increase and IP3 accumulation were attenuated by pretreatment with a phospholipase C inhibitor, U-73122 (5 microM), for 30 min. ATP (10(-5) M) significantly enhanced the proliferation of BCEC. ATP-induced [Ca2+]i increase and cell proliferation were inhibited by a purinoceptor antagonist, suramin (10(-4) M). Thus, the present study indicates that BCEC contain P2 purinoceptors that regulate their proliferation.

Temperature sensitive effects of alpha-adrenergic stimulation in mouse ventricular myocardia

The effects of alpha- and beta-adrenergic stimulation on the contractile force and L-type Ca2+ channel current were studied in mouse ventricular myocardia at two different temperatures. In ventricular tissue, at 35-36 degrees C, phenylephrine, in the presence of propranolol, produced a sustained negative inotropic response with no change in the time course of contraction and relaxation. These effects were greatly reduced at 22-23 degrees C. Isoproterenol produced marked positive inotropic responses accompanied by shortening of the time required for relaxation. In isolated ventricular myocytes, phenylephrine, in the presence of propranolol, significantly increased the L-type Ca2+ channel current (I(Ca)) at 35-36 degrees C, but the effect was small at 22-23 degrees C. Isoproterenol increased I(Ca) similarly at both temperatures. These results suggest that, in mouse ventricular myocardia, alpha-adrenoceptor mediated regulation of the contractile force and I(Ca) involve temperature-dependent mechanisms different from those of beta-adrenoceptor-mediated mechanisms.

Molecular cloning and characterization of multispecific organic anion transporter 4 expressed in the placenta

A cDNA encoding a novel multispecific organic anion transporter, OAT4, was isolated from a human kidney cDNA library. The OAT4 cDNA consisted of 2210 base pairs that encoded a 550-amino acid residue protein with 12 putative membrane-spanning domains. The amino acid sequence of OAT4 showed 38 to 44% identity to those of other members of the OAT family. Northern blot analysis revealed that OAT4 mRNA is abundantly expressed in the placenta as well as in the kidney. When expressed in Xenopus oocytes, OAT4 mediated the high affinity transport of estrone sulfate (K(m) = 1.01 microM) and dehydroepiandrosterone sulfate (K(m) = 0.63 microM) in a sodium-independent manner. OAT4 also mediated the transport of ochratoxin A. OAT4-mediated transport of estrone sulfate was inhibited by several sulfate conjugates, such as p-nitrophenyl sulfate, alpha-naphthyl sulfate, beta-estradiol sulfate, and 4-methylumbelliferyl sulfate. By contrast, glucuronide conjugates showed little or no inhibitory effect on the OAT4-mediated transport of estrone sulfate. OAT4 interacted with chemically heterogeneous anionic compounds, such as nonsteroidal anti-inflammatory drugs, diuretics, sulfobromophthalein, penicillin G, and bile salts, whereas tetraethylammonium, an organic cation, did not. OAT4 is the first member of the multispecific organic anion transporter family, which is expressed abundantly in the placenta. OAT4 might be responsible for the elimination and detoxification of harmful anionic substances from the fetus.

Synthesis and pharmacological activity of O-(5-isoxazolyl)-L-serine

A novel isoxazole derivative, O-(5-isoxazolyl)-L-serine (OIS, 1), was synthesized by a Mitsunobu reaction of isoxazolin-5-one (4) with N-Boc-L-serine tert-butyl ester (5) and subsequent deprotection of the coupling product. Its structure was elucidated by spectroscopic analyses. The pharmacological activity of 1 was also examined with cloned glutamate receptors and transporters using a Xenopus oocyte-expressing system showing substrate activity on an excitatory amino acid carrier 1 (EAAC 1) as a glutamate transporter.

Role of organic anion transporter 1 (OAT1) in cephaloridine (CER)-induced nephrotoxicity

Role of organic anion transporter 1 (OAT1) in cephaloridine (CER)-induced nephrotoxicity.

BACKGROUND

Cephaloridine (CER) has been used to elucidate the mechanisms of cephalosporin antibiotic-induced nephrotoxicity. Organic anion transporters have been thought to mediate CER uptake by the proximal tubule. The purpose of this study was to elucidate the possible involvement of organic anion transporter 1 (OAT1) in CER-induced nephrotoxicity.

METHODS

A mouse terminal proximal straight tubule (S3) cell line stably expressing rat OAT1 (S3 rOAT1) was established and used in this study. The cellular uptake of [14C]-para-aminohippuric acid (PAH), a prototype organic anion, and that of [14C]-CER were measured. The effects of CER on the viability of the cells and the amount of lipid peroxidation were estimated.

RESULTS

S3 rOAT1 expressed a functional organic anion transporter in the cytoplasmic membrane, and exhibited CER uptake activity. CER treatment resulted in a more significant decrease in the viability and a more significant increase in the amount of lipid peroxidation in S3 rOAT1 than in S3 cells transfected with an expression vector lacking the rOAT1 insert. Probenecid, an inhibitor of organic anion transport, and probucol, an antioxidant, significantly suppressed the decrease in viability and increase in the amount of lipid peroxidation in S3 rOAT1 treated with CER. The effects of various cephalosporin antibiotics on the uptake of [14C]PAH were correlated significantly with the effects of these drugs on cell viability.

CONCLUSIONS

These results suggest that rOAT1 is, at least in part, responsible for the cellular uptake of CER and therefore CER-induced nephrotoxicity.