Application of TruGraf v1: A Novel Molecular Biomarker for Managing Kidney Transplant Recipients With Stable Renal Function.

TruGraf v1 is a laboratory-developed DNA microarray-based gene expression blood test to enable proactive noninvasive serial assessment of kidney transplant recipients with stable renal function. It has been previously validated in patients identified as Transplant eXcellence (TX: stable serum creatinine, normal biopsy results, indicative of immune quiescence), and not-TX (renal dysfunction and/or rejection on biopsy results). TruGraf v1 is intended for use in subjects with stable renal function to measure the immune status as an alternative to invasive, expensive, and risky surveillance biopsies. MATERIALS AND METHODS: In this study, simultaneous blood tests and clinical assessments were performed in 192 patients from 7 transplant centers to evaluate TruGraf v1. The molecular testing laboratory was blinded to renal function and biopsy results. RESULTS: Overall, TruGraf v1 accuracy (concordance between TruGraf v1 result and clinical and/or histologic assessment) was 74% (142/192), and a result of TX was accurate in 116 of 125 (93%). The negative predictive value for TruGraf v1 was 90%, with a sensitivity 74% and specificity of 73%. Results did not significantly differ in patients with a biopsy-confirmed diagnosis vs those without a biopsy. CONCLUSIONS: TruGraf v1 can potentially support a clinical decision enabling unnecessary surveillance biopsies with high confidence, making it an invaluable addition to the transplant physician's tool kit for managing patients. TruGraf v1 testing can potentially avoid painful and risky invasive biopsies, reduce health care costs, and enable frequent assessment of patients with stable renal function to confirm the presence of immune quiescence in the peripheral blood.

Investigator Assessment of the Utility of the TruGraf Molecular Diagnostic Test in Clinical Practice.

BACKGROUND: TruGraf v1 is a well-validated DNA microarray-based test that analyzes blood gene expression profiles as an indicator of immune status in kidney transplant recipients with stable renal function. METHODS: In this study, investigators assessed clinical utility of the TruGraf test in patient management. In a retrospective study, simultaneous blood tests and clinical assessments were performed in 192 patients at 7 transplant centers, and in a prospective observational study they were performed in 45 subjects at 5 transplant centers. RESULTS: When queried regarding whether or not the TruGraf test result impacted their decision regarding patient management, in 168 of 192 (87.5%) cases the investigator responded affirmatively. The prospective study indicated that TruGraf results supported physicians' decisions on patient management 87% (39/45) of the time, and in 93% of cases physicians indicated that they would use serial TruGraf testing in future patient management. A total of 21 of 39 (54%) reported results confirmed their decision that no intervention was needed, and 17 of 39 (44%) reported that results specifically informed them that a decision not to perform a surveillance biopsy was correct. CONCLUSIONS: TruGraf is the first and only noninvasive test to be evaluated for clinical utility in determining rejection status of patients with stable renal function and shows promise of providing support for clinical decisions to avoid unnecessary surveillance biopsies with a high degree of confidence. TruGraf is an invaluable addition to the transplant physician's tool kit for managing patient health by avoiding painful and invasive biopsies, reducing health care costs, and enabling frequent assessment of patients with stable renal function to confirm immune quiescence.

Gene Expression in Biopsies of Acute Rejection and Interstitial Fibrosis/Tubular Atrophy Reveals Highly Shared Mechanisms That Correlate With Worse Long-Term Outcomes.

Interstitial fibrosis and tubular atrophy (IFTA) is found in approximately 25% of 1-year biopsies posttransplant. It is known that IFTA correlates with decreased graft survival when histological evidence of inflammation is present. Identifying the mechanistic etiology of IFTA is important to understanding why long-term graft survival has not changed as expected despite improved immunosuppression and dramatically reduced rates of clinical acute rejection (AR) (Services UDoHaH. http://www.ustransplant.org/annual_reports/current/509a_ki.htm). Gene expression profiles of 234 graft biopsy samples were obtained with matching clinical and outcome data. Eighty-one IFTA biopsies were divided into subphenotypes by degree of histological inflammation: IFTA with AR, IFTA with inflammation, and IFTA without inflammation. Samples with AR (n = 54) and normally functioning transplants (TX; n = 99) were used in comparisons. A novel analysis using gene coexpression networks revealed that all IFTA phenotypes were strongly enriched for dysregulated gene pathways and these were shared with the biopsy profiles of AR, including IFTA samples without histological evidence of inflammation. Thus, by molecular profiling we demonstrate that most IFTA samples have ongoing immune-mediated injury or chronic rejection that is more sensitively detected by gene expression profiling. These molecular biopsy profiles correlated with future graft loss in IFTA samples without inflammation.

Ureteral complications in renal transplantation: a comparison of the Lich-Gregoir versus the Taguchi technique.

OBJECTIVE: Modifications of the Lich-Gregoir extravesical ureteroneocystostomy have become the standard technique for management of the ureter during renal transplantation. We performed a comparative outcome examination of the standard Lich-Gregoir technique and the Taguchi or "one-stitch" technique. METHODS: We reviewed our experience at the University of Washington with the Taguchi (one-stitch, Minnesota) extravesical reimplant technique that involves tacking the distal ureter to the bladder mucosa with a single absorbable stitch. RESULTS: During a 3.5-year period, 330 renal transplants were performed and in 73 cases a Taguchi ureteral anastomosis was employed rather than the Lich-Gregoir technique (238 cases). The overall complication rate for the Taguchi technique was 23% (n = 16) as opposed to 7.1% for the Lich-Gregoir technique. When comparing the Taguchi to the Lich-Gregoir technique, there was a significant increase in hematuria and ureteral complications (P = .002, .012). In a multivariate analysis, the Taguchi technique was a significant risk factor for both hematuria and ureteral complications. CONCLUSIONS: In summary, our limited experience with Taguchi ureteroneocystostomy resulted in dramatically higher complication rates than the modified the Lich-Gregoir technique.

Quantitation of BK virus load in serum for the diagnosis of BK virus-associated nephropathy in renal transplant recipients.

BK virus-associated nephropathy is an increasingly recognized cause of graft dysfunction among kidney transplant recipients, and definitive diagnosis requires renal biopsy. By using a newly developed, quantitative, real-time polymerase chain reaction (PCR) assay for BK virus DNA, a retrospective analysis was done of sequential serum samples (n=28) from 4 transplant recipients with histopathologically documented BK virus nephropathy and from samples (n=76) from 16 transplant recipient control patients. BK virus DNA was detected in serum samples from all 4 case patients versus 0 of 16 control patients (P< .0001, Fisher's exact test) at a median of 32 weeks (range, 17-61 weeks) before the diagnosis of BK virus nephropathy. BK virus load decreased in 3 of 3 patients after the reduction of immunosuppression and/or nephrectomy. It is concluded that quantitative PCR for BK virus DNA in serum is useful both for identifying transplant recipients at risk for BK virus nephropathy and for monitoring the response to therapy.

Rescue of acute portal vein thrombosis after liver transplantation using a cavoportal shunt at re-transplantation.

BACKGROUND: Portal vein thrombosis is a rare but devastating complication following orthotopic liver transplantation. Fulminant liver failure ensues with acute portal vein thrombosis after transplantation limiting the treatment options. METHODS: We successfully re-transplanted a 46-year-old female patient who developed acute portal vein thrombosis 19 d after orthotopic liver transplantation. Vascular reconstruction included a cavoportal shunt to augment portal blood flow. RESULTS: Twelve months after re-transplantation this patient lives independently and enjoys excellent liver allograft function. CONCLUSIONS: Cavoportal shunt can augment portal blood flow in adult recipients of orthotopic liver transplants. This technique can be successfully employed during re-transplantation when portal blood flow is inadequate to maintain patency.

Endoscopic treatment of bladder outlet obstruction in men after pancreas transplantation.

PURPOSE: Diabetic cystopathy comprises a spectrum of voiding dysfunction. The usual clinical manifestations are impaired bladder sensation and detrusor contractility. Diabetic cystopathy is present in as many as 43 to 85% of patients undergoing pancreas transplantation. We evaluated endoscopic management of bladder outlet obstruction for adjuvant treatment of urological complications after pancreas transplantation. MATERIALS AND METHODS: We evaluated 10 men with recurrent urological complications, including bladder leak, urinary tract infection, the dysuria/urethritis syndrome and reflux nephropathy, after pancreas transplantation. Evaluation consisted of peak flow rate, post-void residual and written questionnaires in all cases, and preoperative urodynamics in 2. All patients had signs and symptoms of bladder outlet obstruction at post-transplant presentation and underwent bladder neck incision, direct visual internal urethrotomy, limited transurethral resection of the bladder neck or transurethral resection of the prostate. Hospital costs, including operating room, laboratory, pharmacy, hospital room occupancy, anesthesia and radiology fees, were obtained from the University of Washington. RESULTS: Mean peak flow rate plus or minus standard deviation increased from 10.1+/-3.2 to 21.0+/-5.1 cc per second and post-void residual decreased from 259.2+/-38.6 to 43.6+/-36.8 cc after endoscopic intervention. Of the patients 4 presented early (mean 4.3 months) after transplantation with bladder leak or reflux nephropathy, while late presentation (mean 43 months) was associated with recurrent urinary tract infection, the urethritis/dysuria syndrome and more obstructive symptoms. Complications resolved in all cases after surgery and enteric conversion, which costs 5-fold more than endoscopic intervention, was avoided. CONCLUSIONS: Recurrent urological complications warrant early evaluation for occult bladder dysfunction. Endoscopic procedures to relieve outlet obstruction are beneficial in alleviating recurrent urological complications in men after pancreas transplantation. This cost-effective and low morbidity procedure may obviate the need for enteric conversion in some male transplant recipients.

Recombinant human tumor necrosis factor receptor Fc fusion protein therapy in kidney transplant recipients undergoing OKT3 induction therapy.

BACKGROUND: Initial doses of OKT3 are associated with a cytokine-induced acute clinical syndrome (ACS). This study assessed the safety of a recombinant human tumor necrosis factor receptor fusion protein (TNFR:Fc) given to minimize OKT3-ACS symptoms in renal allograft recipients undergoing induction therapy. METHODS: Sixteen patients were randomized into treatment or control groups. Treated patients received TNFR:Fc 1 hr before OKT3 on days 0 and 3. Patients were monitored after transplant for OKT3-ACS symptoms. Levels of cytokines, serum creatinine, and C-reactive protein were followed. RESULTS: Patients receiving TNFR:Fc had lower OKT3-ACS symptoms as measured by a scoring system. There was a higher incidence of infection in treated patients (10/12) compared to controls (1/4) in the 3 months after transplant, but the etiology of this difference was unclear. There were no significant differences in cytokine profiles. CONCLUSIONS: TNFR:Fc is well tolerated by renal transplant patients receiving OKT3 induction therapy and modestly decreases the symptoms associated with OKT3-ACS.

Induction immunosuppressive therapy is associated with a low rejection rate after liver transplantation.

Despite advances in immunosuppression, allograft rejection occurs frequently after liver transplantation. The use of induction therapy with cytolytic antibodies may decrease the frequency of rejection in liver transplant recipients, but may also increase the rate of cytomegalovirus (CMV) infection. It has been our center's strategy to use induction therapy in our liver transplant recipients. To determine the outcome of our strategy, we retrospectively reviewed all liver transplants performed in the first 5 yr of our liver transplant program. The frequency of acute rejection in the first year after liver transplantation was only 34% in patients who received induction therapy. The type of induction therapy antibody did not affect the rejection rate. Clinically significant CMV infection (requiring treatment) occurred in 22% of patients. These results suggest that use of induction therapy with cytolytic antibodies does not lead to a high incidence of CMV infection and decreases the incidence of rejection after liver transplantation.

First-pass metabolism of midazolam by the human intestine.

The in vivo intestinal metabolism of the CYP3A probe midazolam to its principal metabolite, 1'-hydroxymidazolam, was investigated during surgery in 10 liver transplant recipients. After removal of the diseased liver, five subjects received 2 mg midazolam intraduodenally, and the other five received 1 mg midazolam intravenously. Simultaneous arterial and hepatic portal venous blood samples were collected during the anhepatic phase; collection of arterial samples continued after reperfusion of the donor liver. Midazolam, 1'-hydroxymidazolam, and 1'-hydroxymidazolam glucuronide were measured in plasma. A mass balance approach that considered the net change in midazolam (intravenously) or midazolam and 1'-hydroxymidazolam (intraduodenally) concentrations across the splanchnic vascular bed during the anhepatic phase was used to quantitate the intestinal extraction of midazolam after each route of administration. For the intraduodenal group, the mean fraction of the absorbed midazolam dose that was metabolized on transit through the intestinal mucosa was 0.43 +/- 0.18. For the intravenous group, the mean fraction of midazolam extracted from arterial blood and metabolized during each passage through the splanchnic vascular bed was 0.08 +/- 0.11. Although there was significant intersubject variability, the mean intravenous and intraduodenal extraction fractions were statistically different (p = 0.009). Collectively, these results show that the small intestine contributes significantly to the first-pass oxidative metabolism of midazolam catalyzed by mucosal CYP3A4 and suggest that significant first-pass metabolism may be a general phenomenon for all high-turnover CYP3A4 substrates.

The natural history of untreated focal allograft rejection in liver transplant recipients.

Focal rejection involves less than 20% of portal tracts in liver allograft biopsy results. The clinical significance of "focal" rejection on protocol liver biopsy results is unknown. The purpose of this study was to prospectively determine the incidence of clinically significant rejection in patients with focal rejection after orthotopic liver transplantation. Biopsy specimens from 165 consecutive transplantations in 149 patients were analyzed. After protocol biopsy specimens were obtained, patients with focal or mild rejection were observed. Fifty of 583 (8.6%) protocol biopsy results in 41 patients showed focal or mild rejection. None were treated on the basis of this histological finding. Six patients subsequently developed abnormal liver function tests and required treatment with additional immunosuppression. We conclude that focal or mild rejection is a relatively common finding on protocol liver biopsy results and only rarely progresses to a clinically significant problem. Patients with this finding can safely be observed without treatment.

Identification of platelet-derived growth factor A and B chains in human renal vascular rejection.

Platelet-derived growth factor (PDGF) exists as a dimer composed of two homologous but distinct peptides termed PDGF-A and -B chains, and may exist as AA, AB, and BB isoforms. The PDGF-B chain has been implicated as a mediator of renal vascular rejection by virtue of up-regulated expression of its receptor, PDGF beta-receptor, in affected arteries. A role for PDGF-A chain in mediating intimal proliferation has been suggested in human atherosclerosis (Rekhter MD, Gordon D: Does platelet-derived growth factor-A chain stimulate proliferation of arterial mesenchymal cells in human atherosclerotic plaques? Circ Res 1994, 75:410), but no studies of this molecule in human renal allograft injury have been reported to date. We used two polyclonal antisera to detect expression of PDGF-A chain and one monoclonal antibody to detect PDGF-B chain by immunohistochemistry in fixed, paraffin-embedded tissue from 1) normal adult kidneys, 2) a series of renal transplant biopsies chosen to emphasize features of vascular rejection, and 3) allograft nephrectomies. Immunohistochemistry was correlated with in situ hybridization on adjacent, formalin fixed tissue sections from nephrectomies utilizing riboprobes made from PDGF-A and -B chain cDNA. PDGF-A chain is widely expressed by medial smooth muscle cells of normal and rejecting renal arterial vessels of all sizes by immunohistochemistry and in situ hybridization. PDGF-A chain is also expressed by a population of smooth muscle cells (shown by double immunolabeling with an antibody to alpha-smooth muscle actin) comprising the intima in chronic vascular rejection. In arteries demonstrating acute rejection, up-regulated expression of PDGF-A chain by endothelial cells was detected by both immunohistochemistry and in situ hybridization. In contrast, PDGF-B chain was identified principally in infiltrating monocytes within the rejecting arteries, similar to its localization in infiltrating monocytes in human atherosclerosis. Although less prominent than the case for PDGF-A chain, PDGF-B chain also was present in medial and intimal smooth muscle cells in both rejecting and nonrejecting renal arteries. PDGF-A and -B chains have now been localized at both the mRNA and protein levels to the intimal proliferative lesions of vascular rejection. These peptides, which are known stimuli for smooth muscle cell migration and proliferation in experimental vascular injury, may have similar stimulatory effects on smooth muscle cells in an autocrine and/or paracrine manner to promote further intimal expansion and lesion progression in this form of human vasculopathy.

Rationale for total nephrectomy for suspected renal cell carcinoma.

This article discusses the data surrounding a comparison of radical nephrectomy with nephron-sparing surgery in renal car carcinoma with an emphasis on patients with renal cell carcinoma who have normal renal function and contralateral normal anatomy and with special reference to the "case" presentation, which involves a small hilar lesion. The discussion argues in favor of radical nephrectomy in most of these cases.

Application of organ transplant techniques to urologic surgery.

This article presents a detailed description of surgical techniques that have been adapted from multi-organ procurement procedures and liver and pancreas transplantation that may be applied to urologic surgery, specifically difficult excision of urologic tumors in the upper abdomen and retroperitoneum. Techniques for exposure, mobilization of the liver, mobilization of the pancreas and spleen segment, isolation of the suprarenal intra-abdominal inferior vena cava, and the intra-abdominal approach of the intracardiac inferior vena cava through a pericardial window are described. The addition of the described techniques to the urologist's surgical armamentarium may be beneficial for providing increased access and exposure in difficult urologic cases.

Use of ultrasound and cystoscopically guided pancreatic allograft biopsies and transabdominal renal allograft biopsies: safety and efficacy in kidney-pancreas transplant recipients.

The use of allograft biopsies to guide treatment after solid organ transplantation is a valuable tool in the detection and treatment of rejection. Prior development and use of the cystoscopically guided pancreatic allograft biopsy have allowed for more accurate and timely diagnosis of pancreatic allograft dysfunction, possibly contributing to our 1-year pancreas graft, renal allograft and patient survival rates of 87.1%, 88.5% and 96.8%, respectively. We reviewed our experience, examining efficacy and complication rates of pancreas and kidney biopsies in 31 cadaveric pancreas or combined kidney and pancreas transplants performed between June 1990 and February 1992 with at least 1 year of followup. There were 94 pancreas, 54 kidney and 53 duodenal mucosal biopsies in 29 evaluable patients. This biopsy technique uses a 24.5F side-viewing nephroscope to view the cystoduodenostomy, with the duodenum acting as a portal for biopsy needles into the pancreas. Pancreatic tissue is obtained with either an 18 gauge, 500 mm. Menghini aspiration/core needle or an 18 gauge, 500 mm. Roth core needle. Percutaneous renal allograft biopsies are performed independently or simultaneously with the pancreas biopsies using a 16 gauge spring loaded needle. Pancreas biopsies were prompted by clinical indications of rejection (decreased urinary amylase, increased serum amylase or increased serum creatinine) or by protocol (10, 21 and 40 days postoperatively). Among the biopsies 30% were required by protocol, of which 10 (36%) revealed abnormal pathological findings and 5 (18%) showed evidence of occult cellular rejection. Renal biopsies demonstrated rejection in 69% of the cases. Of simultaneous pancreas/kidney biopsies 33% revealed concomitant rejection. A total of 88 Menghini needles with 170 passes was used in 73 biopsy attempts, yielding 126 tissue cores with a 16% complication rate. A total of 41 Roth needles was used with 73 passes in 34 biopsy attempts, yielding 55 tissue cores with a complication rate of 21%. Complications included self-limited bleeding from the biopsy site in 13% of the cases, bleeding requiring clot evacuation and fulguration in 1% and asymptomatic hyperamylasemia in 12%. Renal biopsy complications included 1 arteriovenous fistula (2%). We conclude that ultrasound and cystoscopically guided pancreatic allograft biopsy and percutaneous renal allograft biopsies are safe and essential methods of obtaining tissue for histological diagnosis without serious sequelae. The Menghini and Roth needles in cystoscopically guided pancreatic allograft biopsy have similar yield and complication rates in obtaining pancreatic tissue, although they require different performance techniques. In some cases both needles are necessary and are complementary in obtaining adequate tissue.(ABSTRACT TRUNCATED AT 400 WORDS)

Antiviral prophylaxis and the Epstein Barr virus-related post-transplant lymphoproliferative disorder.

Epstein Barr virus (EBV) infection has been associated with the post-transplant lymphoproliferative disorder (PTLD) in up to 8% of transplant recipients. Primary EBV infection and the use of antilymphocyte preparations appear to increase the incidence of PTLD. Experimental evidence suggests that the antiviral prophylaxis used by many transplant programs may influence the development of this post-transplant complication. In order to investigate the influence of antiviral prophylaxis (intravenous ganciclovir followed by high-dose oral acyclovir) on the development of PTLD in kidney-pancreas and liver allograft recipients from the University of Washington Medical Center, records were reviewed for pretransplant EBV status, antilymphocyte preparation use and for histologic documentation of PTLD. Two of 83 kidney-pancreas recipients (1 EBV-seronegative, 1 EBV-seropositive) and 1 of 123 liver recipients (EBV-seropositive) has developed PTLD. Six of 83 kidney-pancreas patients were EBV-seronegative prior to transplantation and 4 of these patients received at least two courses of an antilymphocyte preparation. Thirty-eight (49%) of the 77 EBV-seropositive kidney-pancreas recipients received at least two courses of an antilymphocyte globulin without the development of PTLD. Both the EBV-seronegative kidney-pancreas and the liver recipient who developed PTLD had received multiple courses of antilymphocyte globulins. One EBV-seropositive kidney-pancreas recipient had only received one course of OKT3 1 year prior to the development of PTLD. The incidence of PTLD reported here in patients receiving intravenous ganciclovir followed by high-dose oral acyclovir antiviral prophylaxis is lower than previously recorded when consideration is given for patient's EBV status and the use of antilymphocyte preparations.

Use of midazolam as a human cytochrome P450 3A probe: I. In vitro-in vivo correlations in liver transplant patients.

The clearance of midazolam (MDZ) in humans is principally due to metabolic biotransformation catalyzed by CYP3A isoforms. A study was conducted in patients who had undergone liver transplants that provides evidence that MDZ can be used as an in vivo probe of interindividual hepatic CYP3A variability. The clearance of MDZ and cyclosporine after i.v. administration were determined in 10 patients approximately 10 days after transplant surgery. Liver biopsy specimens were obtained within 24 hr of the pharmacokinetic study and CYP3A content and MDZ 1'-hydroxylation activity were measured in 13,000 x g tissue supernatants (S-13). The in vitro rate of 1'-hydroxy-MDZ formation was found to correlate significantly with the total CYP3A content in hepatic S-13 fractions (r = .84, P < .01). The total MDZ clearance measured in vivo was highly correlated with the hepatic CYP3A content measured in vitro (r = .93, P < .001) and with in vivo cyclosporine clearance (r = .81, P < .001). For five of the patients, the intrinsic clearance of midazolam to 1'-hydroxy-MDZ (Vmax/Km) in vitro measured in S-13 preparations was scaled for total liver mass and applied to the well stirred model of hepatic clearance to yield a prediction of MDZ clearance in vivo. The mean MDZ clearance predicted from in vitro 1'-hydroxylation data was identical to the mean clearance observed in vivo (0.60 +/- 0.24 versus 0.59 +/- 0.25 liter/min). Together, the results suggest that variability in hepatic CYP3A expression in liver transplant recipients, and possibly in other populations, can be determined by the measurement of MDZ metabolic clearance.

Use of midazolam as a human cytochrome P450 3A probe: II. Characterization of inter- and intraindividual hepatic CYP3A variability after liver transplantation.

Immunosuppression therapy with cyclosporine is often hampered by significant interindividual variability in the metabolic clearance of the drug. It has been suggested that much of the variability in cyclosporine clearance is due to differences in the cytochrome P450 3A4 (CYP3A4) content in the liver and intestinal mucosa. A study was conducted in liver transplant recipients to characterize hepatic CYP3A variability during the first 10 days after surgery. The formation of 1'-hydroxymidazolam (1'-OH MDZ) was followed in the plasma after i.v. midazolam (MDZ) administration to 21 multiple-organ donors and to recipients of 10 of the 21 donor livers. Liver biopsy tissue was obtained from donors and recipients after the in vivo pharmacokinetic test. For liver donors, the plasma 1'-OH MDZ/MDZ concentration ratio 30 min after the i.v. MDZ dose was well correlated with the hepatic CYP3A4 content (r = .87, P < .001). Much of the variability in the two parameters was attributed to the administration of enzyme-inducing drugs before organ procurement. The mean hepatic CYP3A4 content and plasma 1'-OH MDZ/MDZ concentration ratio in six inducer-treated donors was 4.7-fold and 2.3-fold higher than the respective mean value for all other donors. The hepatic CYP3A4 content and plasma 1'-OH MDZ/MDZ ratio for liver recipients, studied on postoperative day 10, was negatively correlated with the respective parameter measured in donors on day 0 (r = -0.60 for CYP3A4 and r = -0.79 for 1'-OH MDZ/MDZ; P < .05 and P < .01).(ABSTRACT TRUNCATED AT 250 WORDS)