PubMed Health⌕ Search

Biomedical subjects

R S Filo

Publications and source records attributed to R S Filo.

At least 19 recordsLinked to original sources
PubMed2006

In vitro monitoring of in vivo development of human anti-thymoglobulin antibodies by ELISA.

Thymoglobulin (rATG), polyclonal immunoglobulin, is prepared from rabbits immunized with human thymocytes. It is effective in prevention and treatment of renal allograft rejection. Human antibodies against antilymphocyte preparations can reduce efficacy by accelerating drug clearance or by inducing serum sickness. We developed an enzyme-linked immunosorbent assay (ELISA) to study posttreatment development of anti-rATG. In an Institutional Review Board-approved trial, we tested 101 allograft recipients for anti-rATG antibodies. Patients received rATG intravenously at 1.25 to 2.0 mg/kg/d for 2 to 14 days. Serum samples were obtained pretreatment and at weeks 1, 2, 4, 6, and months 3 and 6 post-rATG. ELISA plates were coated with rATG (10 microg/mL). Samples were diluted 1:100 and tested in quadruplicate. Positive samples were titrated. Horseradish peroxidase-conjugated (HRPO) affinity-purified goat anti-human immunoglobulin G (H&L) antibody reacted with bound human antibody. A chromagenic substrate for HRPO was added and optical density (OD, 490 nm) was read. An OD of twice the negative control was considered positive. Mean ODs of negative and positive controls were 0.113 +/- 0.030 and 1.042 +/- 0.196, respectively. Ten patients had detectable anti-rATG before rATG administration (1:100). Thirty-five of 101 patients (35%) developed anti-rATG antibody. Patients showed an initial positive anti-rATG antibody from days 8 to 59 after infusion and titers from 1:100 to 1:4000. In spite of rATG's postulated anti-B-cell activity, this study confirms that rATG induces sensitization at a frequency and titer seen with other xenogeneic antilymphocyte antibodies. Formation of such antixenoantibodies can have a negative impact on treatment response and hence warrant monitoring.

Animals↗
PubMed2002

Incidence of histoplasmosis following allogeneic bone marrow transplant or solid organ transplant in a hyperendemic area.

Questions have arisen regarding the risk of developing symptomatic Histoplasma capsulatum infection among patients who undergo transplant-related immunosuppression in areas endemic for histoplasmosis. Our medical center is located in a hyperendemic area for histoplasmosis, where three large outbreaks occurred since 1978. We undertook a retrospective chart review of 137 patients who received allogeneic bone marrow transplant and of 449 patients who received solid organ transplant from January 1994 to December 1996 in order to assess the incidence of active histoplasmosis. Charts were reviewed before and after transplantation for clinical outcomes, H. capsulatum serologies and antigen results, and microbiological and radiological results. After a mean follow-up duration exceeding 16 months, no patient was diagnosed with histoplasmosis. In the absence of an outbreak, histoplasmosis is a rare infection following the immunosuppression of allogeneic bone marrow or solid organ transplantation even in a hyperendemic area. Pre-transplant serologies or chest radiographs consistent with prior infection were not associated with post-transplant histoplasmosis.

Adult↗
PubMed2001

Evaluation of prospective living renal donors for laparoscopic nephrectomy with multisection CT: the marriage of minimally invasive imaging with minimally invasive surgery.

Laparoscopic technique for excision of a kidney from a living donor has advantages over conventional open surgery, but operative visibility and surgical exposure are limited. Preoperative multisection computed tomography (CT) can provide necessary anatomic information in a minimally invasive procedure. A three-phase examination is suggested: (a) imaging from the top of the kidneys to the pubic symphysis with a section width of 2.5 mm and no contrast medium, (b) scanning of the kidneys and upper pelvis during the arterial phase of enhancement with a section width of 1.0 mm, and (c) scanning of the kidneys and upper retroperitoneum during the nephrographic phase of enhancement with a section width of 1.0 mm. Emphasis in this article is placed on analysis of the venous anatomy because most radiologists are unfamiliar with the anatomic variations. Conventional radiography of the abdomen and pelvis is performed after CT to evaluate the collecting system and ureters and to provide a lower total radiation dose than if CT were used. Of several postprocessing techniques that may be used, the authors prefer maximum intensity projection for arterial evaluation and multiplanar reformatting for venous evaluation.

Humans↗
PubMed2000

Is there a role for Chlamydia pneumoniae in hemodialysis vascular access thrombosis?

Significant evidence suggests that Chlamydia pneumoniae has a major role in occlusive vascular disease. Vascular access thrombosis in chronic hemodialysis patients is a frequent problem; the underlying pathological state is stenosis caused by endothelial hyperplasia. There is presently no literature concerning C pneumoniae in vascular access thrombosis. We embarked on a study to evaluate the possible role of C pneumoniae in access failure. Ten consecutive patients with thrombosed polytetrafluoroethylene (PTFE) conduit arteriovenous fistulae undergoing surgical thrombectomy and revision were studied. We sought to detect C pneumoniae using both culture and polymerase chain reaction (PCR) methods. An excisional biopsy of the stenotic vein segment just above the anastomosis with the PTFE graft was obtained at surgery. Vein samples weighing at least 30 mg were aseptically placed in transport media and stored at 4 degrees C for up to 24 hours. The samples then were sonicated, inoculated in Hep-2 cell culture vials containing confluent monolayers, and passaged three times over 2 weeks. Detection was by direct fluorescent antibody staining. Both culture and PCR were performed in an active chlamydia research laboratory. None of the 10 samples was positive for C pneumoniae by culture or PCR. Based on our preliminary pilot study, we do not believe C pneumoniae has a major role in endothelial hyperplasia and consequent graft loss in the hemodialysis patients we studied.

Aged↗
PubMed1999

Bacillary angiomatosis in a renal transplant recipient.

A case of bacillary angiomatosis infection presenting as a skin nodule in a renal transplant recipient was found. The patient was taking cyclosporine, prednisone, and mycophenolate mofetil at the time of presentation. The bacillary angiomatosis responded to 6 months of therapy with oral erythromycin.

Adult↗
PubMed1998

Histopathologic findings from 2-year protocol biopsies from a U.S. multicenter kidney transplant trial comparing tarolimus versus cyclosporine: a report of the FK506 Kidney Transplant Study Group.

BACKGROUND: This paper reports the histopathologic results of 2-year protocol biopsies from patients who were enrolled in the U.S. FK506 kidney transplant study . METHODS: Recipients of cadaveric kidney transplants were randomized to tacrolimus or cyclosporine therapy. Patients active in the trial at 2 years after transplantation were approached for a protocol biopsy. Biopsies were scored by the Banff classification in a blinded fashion by one pathologist. RESULTS: A total of 144 patients (41.3% of those active at 2 years) had a 2-year protocol biopsy performed; 79 patients were treated with tacrolimus and 65 patients were treated with cyclosporine. Evidence of acute rejection was found in seven (8.9%) of the 2-year biopsies in tacrolimus-treated patients and six (9.2%) cyclosporine-treated patients. Chronic allograft nephropathy was found in 49 (62.0%) tacrolimus biopsies and 47 (72.3%) cyclosporine biopsies (P=0.155). There were no apparent histopathologic differences between the tacrolimus and cyclosporine biopsies. The occurrence of chronic allograft nephropathy was significantly higher in patients who received a graft from an older donor (P<0.01), who experienced presumed cyclosporine or tacrolimus nephrotoxicity (P<0.001), who developed a cytomegalovirus infection (P=0.038), or who experienced acute rejection in the first year after transplantation (P=0.045). A multivariate analysis showed that nephrotoxicity and acute rejection were the most significant predictors for chronic allograft nephropathy. CONCLUSIONS: The occurrence of histologic acute rejection was rare at 2 years, confirming the absence of subclinical acute rejection in these late biopsies. A majority of the biopsies showed features consistent with chronic allograft nephropathy that was associated with acute rejection (particularly in cyclosporine-treated patients), nephrotoxicity, and cytomegalovirus infection in the first year. This suggests that nonimmunologic factors, such as drug-induced toxicity, may play an important role in chronic allograft nephropathy.

Adult↗
PubMed1998

Prostate-specific antigen values and their clinical significance in renal transplant recipients.

BACKGROUND: In the diagnosis of prostate cancer, prostate-specific antigen (PSA) is the most clinically useful tumor marker. Its utility in renal transplant patients is unclear. We hypothesized that PSA values might be affected by the renal function, immunosuppression, or proteinuria. METHODS: Three hundred four PSA values were measured in 166 patients >40 years (53.5 +/- 7.2 years, mean +/- SD, range 44.4 to 76.2). Charts were reviewed for 24-hour creatinine clearance, 24-hour urinary protein, cyclosporine use, age at the time of each PSA test, and evaluation done in response to the PSA result. Analyses used the Mann-Whitney U test and simple regression model. RESULTS: Twenty-five values in 13 patients were >4.0 ng/mL. Of these, 6 patients (6 values) had normal repeat PSA values; 3 patients (11 values) had negative evaluations for prostate cancer; and 4 patients (8 values) were diagnosed with prostate cancer. The latter 4 patients were excluded from the denoted normal group leaving 294 PSA values in 162 patients. The mean normal PSA was 1.3 +/- 1.8 ng/mL, range 0.1 to 20.2. The pretreatment mean PSA for recipients with prostate cancer was 302 +/- 800, range 8.0 to 2,281. An elevated PSA value was associated with a 31% incidence of prostate cancer. There was no association of PSA levels with cyclosporine use, 24-hour creatinine clearance, or 24-hour urinary protein, but there was with age. CONCLUSIONS: Prostate-specific antigen values in renal transplant recipients are similar to those in the general population and are not influenced by cyclosporine or by renal function. We recommend routine measurement of PSA in male transplant recipients.

Adult↗
PubMed1997

Predictive value of enzyme-linked immunosorbent assay-detected IgG anti-HLA antibodies for pediatric renal allograft rejection.

BACKGROUND: Measurement of panel-reactive antibody (PRA) with an enzyme-linked immunosorbent assay using soluble HLA class I molecules (PRA-STAT) in adult renal transplant recipients predicted graft loss and rejection. We sought to confirm this finding in pediatric recipients, an immunologically distinct group. METHODS: The population consisted of 158 renal transplants in 146 patients (age range, 1-21 years). PRA was determined with PRA-STAT and microlymphocytotoxicity (CDC), using final cross-match sera. An elevated test was defined as > or =5% reactivity. Statistical analysis for rejection used the chi-square test and for graft survival used the log-rank test. RESULTS: Thirty-five patients (22%) had %PRA-STAT > or =5%, compared with 26 (16%) with %PRA-CDC > or =5%. The percentage with elevated %PRA-STAT was found to correlate with subsequent transplantations (first, 15%; second, 67%; third, 75%). Subsequent analyses utilized only the 136 primary recipients, of whom 20 (15%) had %PRA-STAT > or =5% and 16 (12%) had %PRA-CDC > or =5%. Elevated %PRA-STAT correlated with rejection at 3 months (65% vs. 36%), 12 months (84% vs. 50%), and 24 months (84% vs. 54%) (P<0.05). No association was found between elevated %PRA-CDC and rejection. Patients with %PRA-STAT > or =5% vs. %PRA-STAT <5% had graft survival at 1 year of 89% vs. 84%, at 2 years of 88% vs. 77%, and at 3 years of 61% vs. 72% (not significant). CONCLUSIONS: Use of %PRA-STAT > or =5% identifies pediatric recipients who are at increased risk for rejection and may benefit from more potent immunosuppression and/or closer monitoring of graft function.

Adolescent↗
PubMed1997

A comparison of tacrolimus (FK506) and cyclosporine for immunosuppression after cadaveric renal transplantation. FK506 Kidney Transplant Study Group.

BACKGROUND: Tacrolimus (FK506), a macrolide molecule that potently inhibits the expression of interleukin 2 by T lymphocytes, represents a potential major advance in the management of rejection following solid-organ transplantation. This randomized, open-label study compared the efficacy and safety of tacrolimus-based versus cyclosporine-based immunosuppression in patients receiving cadaveric kidney transplants. METHODS: A total of 412 patients were randomized to tacrolimus (n=205) or cyclosporine (n=207) after cadaveric renal transplantation and were followed for 1 year for patient and graft survival and the incidence of acute rejection. RESULTS: One-year patient survival rates were 95.6% for tacrolimus and 96.6% for cyclosporine (P=0.576). Corresponding 1-year graft survival rates were 91.2% and 87.9% (P=0.289). There was a significant reduction in the incidence of biopsy-confirmed acute rejection in the tacrolimus group (30.7%) compared with the cyclosporine group (46.4%, P=0.001), which was confirmed by blinded review, and in the use of antilymphocyte therapy for rejection (10.7% and 25.1%, respectively; P<0.001). Impaired renal function, gastrointestinal disorders, and neurological complications were commonly reported in both treatment groups, but tremor and paresthesia were more frequent in the tacrolimus group. The incidence of posttransplant diabetes mellitus was 19.9% in the tacrolimus group and 4.0% in the cyclosporine group (P<0.001), and was reversible in some patients. CONCLUSIONS: Tacrolimus is more effective than cyclosporine in preventing acute rejection in cadaveric renal allograft recipients, and significantly reduces the use of antilymphocyte antibody preparations. Tacrolimus was associated with a higher incidence of neurologic events, which were rarely treatment limiting, and with posttransplant diabetes mellitus, which was reversible in some patients.

Acute Disease↗
PubMed1997

Intraoperative placement of a Wallstent for portal vein stenosis and thrombosis after liver transplantation.

We report a case of orthotopic liver transplantation, in which portal vein thrombosis developed in the immediate postoperative period. Surgical thrombectomy and intraoperative placement of a large caliber Wallstent resulted in long-term patency. The unique feature of this case is the intraoperative placement of the stent via the inferior mesenteric vein under fluoroscopic guidance. The use of a large caliber (16 mm) stent obviated the need for postoperative anticoagulation.

Adult↗
PubMed1997

Oral ganciclovir in pediatric transplant recipients: a pharmacokinetic study.

An oral formulation of ganciclovir (GAN) has been shown to be effective as prophylaxis of cytomegalovirus (CMV) after liver transplantation in an adult population. There are no data on the use or dose of oral GAN in pediatric transplant recipients. We evaluated the pharmacokinetics of oral GAN in a group of such patients. Nine patients (4 kidney and 5 liver transplant recipients, age 0.9-13 yr) were treated with the commercial formulation of oral GAN after transplant. All patients were considered at risk for CMV disease based on the use of anti-lymphocyte antibody (n = 5), and/or the use of a CMV positive organ in a CMV negative recipient (n = 5) or based on being a recipient of a liver transplant (n = 4). They received oral GAN for 84 +/- 29 d. All recipients had normal renal function as estimated by the Schwartz formula. While on a stable dose of oral GAN for at least 4 d (mean +/- SD 8.4 +/- 7, range 4-27 d), 1-ml serum samples were obtained before and at various times after dosing for the measurement of GAN levels. GAN levels were determined at a central laboratory by high-performance liquid chromatography. In 7 of the patients, a sufficient number of levels were obtained post-dosing to calculate the area under the curve using the linear trapezoidal rule. Cmin, the morning trough concentration, and Cmax, the peak concentration, were determined by inspection. Doses of oral GAN were increased if Cmin levels were less than 0.5-1.0 microgram/ml. Adequate levels of GAN were achieved in these patients at doses of 21.8-38.5 mg/kg or 568-990 mg/m2 every 8 h. There was a better correlation between the maximum GAN blood concentration and body surface area (R2 = 0.52, p = 0.008) than with body weight (R2 = 0.36, p = 0.04). Oral GAN was well tolerated in the 7 patients without evidence of leukopenia, thrombocytopenia, or nephrotoxicity. No CMV disease occurred, although one patient had probable CMV syndrome with the development CMV IgM antibodies. These data suggest that oral GAN may be safely administered to pediatric transplant recipients. With normal renal function, the dosing should be in the range 20-40 mg/kg or 500-700 mg/m2 q 8 h. Further data in children with impaired renal function is required.

Administration, Oral↗
PubMed1996

Institutional variation in hemotherapy for solid organ transplantation.

BACKGROUND: Solid organ allograft recipients may require large amounts of blood components. The modification of components to make them safer for iatrogenically immunosuppressed transplant patients increases workload demands on blood banks and transfusion services. STUDY DESIGN AND METHODS: Institutions within the United States and Canada providing hemotherapy as support for transplant recipients were surveyed for their transfusion practices. RESULTS: Responses from 25 institutions provide the data for this report. In 1991, the mean intraoperative red cell requirements ranged from <1 unit for renal allograft recipients to 17.3 units for liver transplant recipients. The latter group also required the greatest amounts of platelets, fresh-frozen plasma, and cryoprecipitate. More than 75 percent of responding institutions provided either cytomegalovirus-seronegative or white cell-reduced cellular components to pediatric recipients of liver allografts and to both adult and pediatric recipients of heart, lung, and heart-lung allografts. The use of irradiated cellular blood components, although uncommon, was greatest in heart transplant recipients. The use of pretransplantation transfusions for immunomodulation was generally limited to patients awaiting a living-donor renal transplant. CONCLUSION: Transfusion practices varied among the institutions, but the majority provide cytomegalovirus-safe cellular blood components to heart and lung allograft recipients and to pediatric transplant patients. Gamma-radiated cellular components are not routinely provided to patients undergoing solid organ transplantation. Liver allograft recipients require the greatest amount of hemotherapeutic support.

Adult↗
PubMed1996

Pulmonary emboli from pulse-spray and mechanical thrombolysis: evaluation with an animal dialysis-graft model.

PURPOSE: To compare pulmonary emboli resulting from pulse-spray pharmacomechanical thrombolysis (PSPMT) and mechanical thrombolysis performed to declot dialysis-access grafts. MATERIALS AND METHODS: Polytetrafluoroethylene arteriovenous shunts were created in eight dogs and were deliberately clotted at monthly intervals. Animals were randomly assigned to treatment with pulse-spray urokinase thrombolysis or a low-speed rotational percutaneous thrombolytic device. Perfusion imaging, pulmonary-artery pressure measurements, and pulmonary arteriography were performed before and after each procedure. RESULTS: A total of 22 procedures were performed (11 PSPMT and 11 mechanical thrombolysis). Declotting was successful in all procedures, with 100% 30-day patency. Segmental defects were seen on perfusion images after 10 (91%) of 11 PSPMT procedures and two (18%) of 11 mechanical thrombolysis procedures (P < .002). Transient increases in pulmonary-artery pressure occurred in the PSPMT group. Complete resolution of emboli and return to baseline pressures were seen in all cases, even after multiple (up to four) procedures in the same animal. There was no histologic evidence of pulmonary infarction in either group. CONCLUSION: The percutaneous thrombolytic device is effective for declotting dialysis grafts in dogs and results in statistically significantly fewer pulmonary emboli compared with PSPMT.

Animals↗
PubMed1996

Proteinuria in recipients of liver transplants.

We investigated the incidence and significance of proteinuria in recipients of liver transplants. The overall incidence of proteinuria was 59.72%. The peak incidence of proteinuria was at 3 months and at the end of 1 yr posttransplant. Proteinuria was higher in those patients who developed posttransplant diabetes mellitus, and those who developed both posttransplant diabetes and posttransplant hyperlipidemia. Patients who received higher total dosage of steroids and CsA had significantly greater proteinuria. Patients who had a Cr Cl greater than 50 ml/min had greater proteinuria posttransplant for the first 6 months, but the trend was reversed later. We did not find any association of proteinuria with age, weight, rejection episodes, or with the etiology of liver failure. Hypertension was a common occurrence in our patients, and therefore its significance in the causation of proteinuria could not be defined.

Adolescent↗