Polyoma viral infection in renal transplantation: the role of immunosuppressive therapy.

BACKGROUND: Polyoma virus infection in renal transplant recipients has been observed with increasing frequency in recent years. Renal allograft involvement in this condition may occur as a result of primary infection or secondary to reactivation of the latent virus. Interstitial nephritis, ureteric stenosis, rise in serum creatinine and allograft function loss have been attributed to this viral infection. METHODS: In this study we reviewed our experience with 8 patients who developed polyoma viral infection confirmed by allograft biopsy. All patients were receiving mycophenolate mofetil as part of the immunosuppression and 7 of the 8 patients were on tacrolimus. All patients have biopsy proven polyoma viral infection. The following therapeutic maneuvers were carried out following the diagnosis of polyoma viral infection: 1) stopping mycophenolate and 2) switching tacrolimus to cyclosporine or reducing the tacrolimus dose to adjust it at a lower therapeutic trough level. The clinical course and outcome of our patients were reviewed in relation to manipulation of immunosuppressive medications. RESULTS: The incidence of this infection in our transplant program in the last 3 yr was 5.3%. Seventy-five percent of the patients had at least one rejection episode and 63% had more than one rejection episode. The main risk factor for the development of polyoma viral infection was related to the intensity of immunosuppression. The use of antirejection therapy after histological diagnosis of polyoma virus infection was not associated with improvement of renal function despite the histological appearance of acute rejection. Thus, the interstitial nephritis associated with polyoma viral infection appears to be an inflammatory response to the virus rather than acute rejection. Six out of the 8 patients stabilized renal function with reduction in immunosuppression. CONCLUSIONS: Reduction in immunosuppression was associated with the stabilization of renal function when instituted early. However, these patients were left with a degree of allograft dysfunction and their outcome may be significantly compromised. The lack of effective antiviral therapy for polyoma virus may limit the use of newer and more potent immunosuppressive medications.

"General surgical pearls" for the anterior exposure of vertebral fractures.

Recently interest has been increasing in the anterior surgical approach for spinal cord decompression and bony stabilization of vertebral compression fractures. Our neurosurgical spine service routinely consults us to provide anterior operative exposure and wound closure for all levels of the thoracic and lumbar vertebral spine. Averaging about 30 exposures per year we have developed an excellent operative experience with these vertebral exposures. With no complete general surgery reference on anterior vertebral identified this summary of our "general surgical pearls" that we have learned and/or have developed should significantly aid other general and trauma surgeons who may be asked by their neurosurgical and/or orthopedic surgical colleagues for assistance with these operations.

The Rumel technique for lateral thoracotomy closure.

The closure of the commonly used lateral thoracotomy incision usually includes pericostal sutures which encircle the ribs. Risks of these pericostal sutures include the injury and/or the entrapment of the intercostal neurovascular bundle located along the inferior underedge of each rib. The simple adaptation of the Rumel tourniquet technique is described as an aid for the primary closure of a lateral thoracotomy which may avoid some of the potential complications inherent to thoracotomy incisions.

Herbal supplements: a potential for drug interactions in transplant recipients.

BACKGROUND: Herbal dietary supplements represent a potential and possibly an overlooked cause for drug interactions in transplant recipients. METHODS: Two patients are reported which suggest that St. John's Wort (SJW) may induce cytochrome P-450 3A4 activity and/or P-glycoprotein expression. Both of these mechanisms are significantly involved in the metabolism and absorption of cyclosporine (CSA) and other immunosuppressants. RESULTS: After two renal transplant recipients started self-medicating with SJW, their CSA concentrations were consistently documented to be subtherapeutic. While on SJW, one patient developed acute graft rejection due to low CSA concentrations. In both patients, termination of SJW returned their CSA concentrations to therapeutic values. CONCLUSIONS: Patients taking SJW concomitantly with CSA or other medications whose absorption and metabolism are mediated by cytochrome P-450 and/or P-glycoprotein should require close monitoring. Potential herb-prescription drug interactions are not just limited to SJW. Inquiries regarding the usage of herbal supplements should be an integral component of a transplant recipient's medication history.

The tolerability of newer immunosuppressive medications in a patient with acute intermittent porphyria.

Acute intermittent porphyria results from a deficiency of the porphobilinogen deaminase enzyme of heme biosynthesis and is commonly exacerbated by a wide variety of medications. When referred a patient with acute intermittent porphyria for a renal transplant, only steroids and azathioprine were discovered as safe in patients with acute intermittent porphyria. The administration of many newer immunosuppressive medications, including calcineurin inhibitors, has not been documented in acute intermittent porphyria. Actually, cyclosporine is presently considered contraindicated in acute intermittent porphyria. To determine if calcineurin inhibitors would be tolerated in acute intermittent porphyria, cyclosporine and tacrolimus were administered pretransplant and were documented not to exacerbate acute intermittent porphyria. A successful renal transplant was then performed using tacrolimus. This is the first reported patient with documented acute intermittent porphyria to tolerate safely several of the newer immunosuppressive medications, including tacrolimus, mycophenolate, and rabbit antithymocytic globulin following renal transplantation. This patient's pretransplant evaluation also suggested that cyclosporine may be safe for some patients with acute intermittent porphyria.

Pretransplant evaluation of a patient with acute intermittent porphyria.

The pretransplant evaluation of a patient with a rare diagnosis requires knowledge of the pathophysiology and the transplant literature. A 55-year-old man presented with hypertensive kidney failure and the clinical diagnosis of acute intermittent porphyria. Complications of acute intermittent porphyria, which is a defect of heme production, are due to the accumulation of heme intermediates often precipitated by medications. Based on animal data, cyclosporine is considered unsafe in patients with acute intermittent porphyria. As part of the pretransplant evaluation, the patient received separate trials of tacrolimus and cyclosporine, which did not stimulate his acute intermittent porphyria. Four months after a kidney transplant, the patient still had no signs of rejection or symptoms of acute intermittent porphyria. This is the first documented patient with acute intermittent porphyria who successfully received a kidney transplant using tacrolimus. Because of individual variations, pretransplant testing of calcineurin inhibitors should be continued in patients with acute intermittent porphyria.

St John's wort: a hidden risk for transplant patients.

Herbal medications may cause prescription drug interactions in transplant recipients. After 2 of our kidney transplant recipients started self-medicating with St John's wort, their cyclosporine concentrations were consistently documented to be subtherapeutic. While on St John's wort, one patient developed acute rejection possibly due to low cyclosporine concentrations. Termination of St John's wort returned both patients' cyclosporine concentrations to therapeutic values. Based on the Naranjo Adverse Drug Reaction Probability Scale, our report would achieve a "probable" score, which supports the existence of a St John's wort-cyclosporine adverse drug interaction. St John's wort may induce cytochrome P-450 3A4 activity and/or P-glycoprotein expression, which are both involved in the metabolism and absorption of cyclosporine. Patients using St John's wort concomitantly with cyclosporine or other medications with similar absorption and/or metabolism to cyclosporine need close monitoring. Transplant coordinators are in a critical position to educate transplant recipients about the potential risks of herbal medication usage.

Glucuronidation of estrogens and retinoic acid and expression of UDP-glucuronosyltransferase 2B7 in human intestinal mucosa.

We have recently shown that, in human intestine, glucuronidation of androsterone and testosterone was on the nanomolar level and increased from proximal to distal intestine. In the present study, we have characterized estrogen UDP-glucuronosyltransferase activity in microsomes from intestine of seven human subjects. Intestinal microsomes from all segments of intestine from both males and females (except for one male) glucuronidated estrone (0.2-2.6 nmol/mg x min) and estradiol (0.5-3.1 nmol/mg x min) at levels 2 to 15 times higher than found with human liver microsomes (0.04-0.1 and 0.16-0.25 nmol/mg x min, for estrone and estradiol, respectively). Only with estriol were there significant hepatic glucuronidation (2. 2-4.5 nmol/mg x min) and intestinal glucuronidation activities (0.2-2.2 nmol/mg x min) that were lower than those in liver. All-trans-retinoic acid was glucuronidated by all segments of intestine from both sexes at levels 50 to 80% of those found with human liver but quite low compared with estrogen glucuronidation. In the two subjects for whom stomach was available, there was no measurable activity in stomach microsomes toward any of the substrates. UGT2B RNA expression was examined in mucosa from stomach to colon from two subjects. There was significant expression of UGT2B7, but not of UGT2B4 or UGT2B15, in all segments of intestine. To our knowledge, this is the first direct demonstration of glucuronidation of estrogens by human intestinal microsomes. Thus, in humans, the intestine may be considered as part of the overall mechanism of detoxification via glucuronidation.

Drug interaction between St. John's wort and cyclosporine.

OBJECTIVE: To report a probable drug interaction between the herbal dietary supplement St. John's wort and cyclosporine. CASE REPORT: A 29-year-old white woman who received a cadaveric kidney and pancreas transplant, with stable organ function and stable cyclosporine concentrations began self-medicating with St. John's wort. After taking St. John's wort supplements for four to eight weeks, her cyclosporine concentrations became subtherapeutic; this was associated with organ rejection. Four weeks after stopping St. John's wort, her cyclosporine concentrations again became therapeutic. Subsequent to this rejection episode, she has developed chronic rejection and now has returned to dialysis. DISCUSSION: St. John's wort is suspected to be a significant inducer of CYP3A4 isoenzyme activity and of P-glycoprotein (P-gp) expression, both of which are important in the metabolism and absorption of cyclosporine. Cyclosporine exhibits a relatively small therapeutic window and is sensitive to medications that can modulate the CYP3A4 isoenzyme and P-gp in both the liver and small intestines. CONCLUSIONS: Patients taking St. John's wort concomitant with other prescription medications whose absorption and metabolism are mediated by the CYP3A4 isoenzyme and P-gp require close monitoring. Patient medication histories should include inquiries into the use of herbal dietary supplements.

The aneurysm detection and management study screening program: validation cohort and final results. Aneurysm Detection and Management Veterans Affairs Cooperative Study Investigators.

BACKGROUND: We previously reported the prevalence and associations of abdominal aortic aneurysm (AAA) in 73451 veterans aged 50 to 79 years who underwent ultrasound screening. OBJECTIVE: To understand the prevalence of and principal positive and negative risk factors for AAA, and to assess reproducibility of our previous findings. METHODS: In the new cohort of veterans undergoing screening, 52 745 subjects aged 50 to 79 without history of AAA underwent successful ultrasound screening for AAA, after completing a questionnaire on demographics and potential risk factors. RESULTS: We detected AAA of 4.0 cm or larger in 613 participants (1.2%; compared with 1.4% in the earlier cohort). The direction and magnitude of the important associations reported in the first cohort were confirmed. Respective odds ratios for the major associations with AAA for the second and for the combined cohorts were as follows: 1.81 and 1.71 for age (per 7 years), 0.12 and 0. 18 for female sex, 0.59 and 0.53 for black race, 1.94 and 1.94 for family history of AAA, 4.45 and 5.07 for smoking, 0.50 and 0.52 for diabetes, and 1.60 and 1.66 for atherosclerotic diseases. The excess prevalence associated with smoking accounted for 75% of all AAAs of 4.0 cm or larger in the total population of 126 196. Associations for AAA of 3.0 to 3.9 cm were similar but tended to be somewhat weaker. CONCLUSIONS: Our findings confirm our previous cohort findings. Age, smoking, family history of AAA, and atherosclerotic diseases remained the principal positive associations with AAA, and female sex, diabetes, and black race remained the principal negative associations.

The Rumel technique. An aid for difficult diaphragmatic closures.

The inherent weakness of repairing the surgically divided respiratory diaphragm is that it is a muscle to muscle closure which can easily tear. During the thoracoabdominal exposure of the thoracolumbar vertebrae, the left hemidiaphragm is divided circumferentially. Possible due to unique conditions related to these operations the diaphragm could not initially be reapproximated primarily in about 20% of the patients. A modified Rumel technique is described as an aid for closing these difficult divided diaphragms. This simple techniques succeeds by distributing the wound tension along the entire diaphragmatic suture line and not on one suture especially while being tied.

Surgical complications from hemostatic puncture closure devices.

BACKGROUND: For securing immediate hemostasis following percutaneous arterial catheterization, the Food and Drug Administration has approved three hemostatic puncture closure devices. We reviewed our institutional experience with one device (Angio-Seal). METHODS: A retrospective, single-center, nonrandomized observational study was made of all vascular complications following femoral cardiac catheterization. RESULTS: An immediate mechanical failure of the device was experienced in 34 (8%) patients. Surgical repair was required in 1.6% (7 of 425) of patients following Angio-Seal versus 0.3% (5 of 1662) following routine manual compression (P = 0.004). In 5 patients, the device caused either complete occlusion or stenosis of the femoral artery. The polymer anchor embolized in 1 patient and was retrieved with a balloon catheter at surgery. CONCLUSION: During the first year of utilization of a percutaneous hemostatic closure device following cardiac catheterization, we observed a marked increase in arterial occlusive complications requiring surgical repair. Surgeons must be familiar with the design of these devices to achieve precise repair of surgical complications.

Hyperhomocysteinemia increases intimal hyperplasia in a rat carotid endarterectomy model.

PURPOSE: This preliminary study investigated the ability to elevate the serum homocysteine (H[e]) levels and investigated the increases in postoperative neointimal hyperplasia (IH) in an environment with hyperhomocysteinemia and the resultant restenosis in a rat carotid endarterectomy (CEA) model. METHOD: The 9 rats for the control group were fed rat chow, and the 8 rats for the H(e) group were fed H(e)-supplemented rat chow for 2 weeks before and after CEA. The animals underwent anesthesia, and a left common CEA was performed. After 14 days, the serum H(e) levels were measured and the left carotid artery was harvested and elastin stained. Morphometric measurements were used to calculate the area of stenosis of the lumen. The mean and the standard deviation of the mean were determined. The 2 groups were compared with the Mann-Whitney test and a linear regression model. Three additional rats per group were studied, with carotid artery sectioning with double immunohistochemical staining for 5-bromodeoxyuridine (BrdU) and alpha-smooth muscle (alpha-SM) actin. RESULTS: The serum H(e) level in the H(e) group was 36.32 micromol/L +/- 15.28, and in the control group the level was 5.53 micromol/L +/- 2.06 (P =.0007). IH presented as percent lumen stenosis was 21.89% +/- 4.82% in the H(e) group and 4.82% +/- 1.64% in the control group (P =.0007). The linear regression model of the serum H(e) levels and the percent stenosis showed a linear relationship (r2 =.72). The alpha-SM actin staining revealed that nearly all of the cells in the IH area were of smooth muscle or myofibroblast origin and that 10.1% +/- 2.6% of the cells were stained for BrdU in the control group versus 23% +/- 7.1% in the H(e) group. Also, 9.3% +/- 2.6% of the cells in the IH area were stained for BrdU and for alpha-SM actin versus 19.1% +/- 5. 6% stained for both BrdU and alpha-SM actin in the H(e) group. CONCLUSION: This is the first study to examine IH after CEA and hyperhomocysteinemia in rats. The study shows that the elevation of serum H(e) levels can be obtained by feeding rats modified diets with added H(e). The consistent elevation of serum H(e) levels was associated with more than 4 times the amount of IH after a CEA in a rat model.

UDP-glucuronosyltransferases in human intestinal mucosa.

While UDP-glucuronosyltransferases (UGTs) are known to be expressed at high levels in human liver, relatively little is known about extrahepatic expression. In the present study, UGT2B family isoforms involved in the glucuronidation of steroid hormones and bile acids have been characterized in microsomes prepared from jejunum, ileum and colon from six human subjects. Glucuronidation of androsterone and testosterone was highly significant and increased from proximal to distal intestine. In contrast, hyodeoxycholic acid was glucuronidated at a low level in jejunum and ileum and activity was barely detectable in colon. No significant glucuronidation of lithocholic acid was found. Small phenols were glucuronidated with much lower activity than found in liver. High levels of UGT protein were detected with polyclonal anti-rat androsterone- and testosterone-UGT antibodies, whereas UGT2B4, a major hepatic hyodeoxycholic acid-specific UGT, was undetectable using a highly specific anti-human UGT2B4 antibody. Screening for RNA expression by RT-PCR confirmed the absence of UGT2B4 and UGT1A6 and showed expression of UGT2B7, a hepatic isoform shown to glucuronidate androsterone, in all intestinal segments. To our knowledge, the presence of functional androsterone and testosterone directed isoforms in human intestine is a novel finding which supports the idea that the intestinal tract functions as a steroid-metabolizing organ and plays a significant role in steroid hormone biotransformation.

An improved retractor for the anterior approach in the surgical management of vertebral fractures.

Interest appears to be increasing in the anterior approach for the surgical management of thoracic and lumbar vertebral fractures. However, adequate exposure requires a self-retaining retractor system. Current stainless steel systems, by interfering with fluoroscopic visualization of bony fractures and landmarks, require frequent repositioning. We found that a newly available aluminum alloy retractor system provides excellent operative exposure without significant fluoroscopic obstruction. This system eliminates the frustration of frequent retractor repositioning and saves us an average of 20 to 30 minutes of operating room time per vertebral repair.

Comparison of DNA adduct levels associated with oxidative stress in human pancreas.

DNA adducts associated with oxidative stress are believed to involve the formation of endogenous reactive species generated by oxidative damage and lipid peroxidation. Although these adducts have been reported in several human tissues by different laboratories, a comparison of the levels of these adducts in the same tissue samples has not been carried out. In this study, we isolated DNA from the pancreas of 15 smokers and 15 non-smokers, and measured the levels of 1,N6-etheno(2'-deoxy)guanosine (edA), 3, N4-etheno(2'-deoxy)cytidine (edC), 8-oxo-2'-deoxyguanosine (8-oxo-dG), and pyrimido[1,2-alpha]purin-10(3H)-one (m1G). Using the same DNA, the glutathione S-transferase (GST) M1, GSTT1, and NAD(P)H quinone reductase-1 (NQO1) genotypes were determined in order to assess the role of their gene products in modulating adduct levels through their involvement in detoxification of lipid peroxidation products and redox cycling, respectively. The highest adduct levels observed were for m1G, followed by 8-oxo-dG, edA, and edC, but there were no differences in adduct levels between smokers and non-smokers and no correlation with the age, sex or body mass index of the subject. Moreover, there was no correlation in adduct levels between edA and eC, or between edA or edC and m1G or 8-oxo-dG. However, there was a significant correlation (r=0.76; p<0.01) between the levels of 8-oxo-dG and m1G in human pancreas DNA. Neither GSTM1 nor NQO1 genotypes were associated with differences in any of the adduct levels. Although the sample set was limited, the data suggest that endogenous DNA adduct formation in human pancreas is not clearly derived from cigarette smoking or from (NQO1)-mediated redox cycling. Further, it appears that neither GSTM1 nor GSTT1 appreciably protects against endogenous adduct formation. Together with the lack of correlation between m1G and edA or edC, these data indicate that the malondialdehyde derived from lipid peroxidation may not contribute significantly to m1G adduct formation. On the other hand, the apparent correlation between m1G and 8-oxo-dG and their comparable high levels are consistent with the hypothesis that m1G is formed primarily by reaction of DNA with a base propenal, which, like 8-oxo-dG, is thought to be derived from hydroxyl radical attack on the DNA.

The enteric drained pancreas transplant: another potential source of gastrointestinal bleeding.

With most combined kidney and pancreas transplants the transplant pancreatic exocrine secretions are managed with urinary bladder drainage. Because of the associated metabolic and infectious complications, many pancreatic transplants require later conversion to enteric drainage, and the trend in this country is now toward primary enteric drainage. Unlike with urinary bladder drainage when direct cystoscopy can be performed, a disadvantage with enteric drainage is that problems such as bleeding from a transplanted pancreas and attached duodenal segment are not easily evaluated. A case of a cytomegalovirus-related bleeding ulcer in an enteric drained pancreas is presented, along with a review of the possible diagnostic evaluation.