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Biomedical subjects

D Ranjan

Publications and source records attributed to D Ranjan.

At least 19 recordsLinked to original sources

Financial analysis of potential donor management at a medicare-approved transplant hospital.

The purpose of this study was to perform a financial analysis of severe brain injured (SBI) patient management to determine potential reimbursement versus net losses in relation to organ donation and transplantation at a transplant center. We undertook a retrospective analysis of financial records of medically suitable referrals to the organ procurement organization (OPO) from our institution for fiscal years 2002-2003. This included (1) hospital cost and reimbursement, (2) OPO reimbursement for actual donors, (3) financial returns on local transplant activity solely supported by local donor activity and (4) Medicare incentives for local organ donation. There were 48 potential and 18 organ donors for this period. The consent rate reduced from 50% to 25% if family was offered withdrawal of care. After reimbursements from OPO, Medicare incentives and kidney transplant activity solely supported by local organ donation were figured in, the total returns were 244% of total cost of SBI patient management. Aggressive proactive management of severely brain injured patients remains a good medical practice. For Medicare-approved transplant centers, there are additional financial incentives to aggressively treat these patients and pursue organ donation. Prematurely offering withdrawal of care negatively impacts on the organ donation process and hurts institutions financially.

Brain Injuries↗

Vitamin E inhibits cyclosporin A and H2O2 promoted Epstein-Barr virus (EBV) transformation of human B cells as assayed by EBV oncogene LMP1 expression.

BACKGROUND: We have previously shown that oxidative stress induced by H2O2 or cyclosporin A (CsA) can promote Epstein-Barr virus (EBV) transformation of human B cells as analyzed by colony formation, cell number, and by 3H-thymidine incorporation. In this report, we used EBV oncogene LMP1 as a marker to analyze H2O2 or CsA promotion of EBV transformation of human B cells and to test whether antioxidant vitamin E could inhibit H2O2 or CsA promoted LMP1 expression in the EBV-infected cells. MATERIALS AND METHODS: Human splenocytes were prepared by centrifugation and plating technique to provide a greater than 80% pure preparation of B cells and were used for EBV infection. The EBV infected cells were treated with H2O2 (0.1 mM, 10 min), or with CsA (500 ng/ml) with or with out vitamin E (40 microM). The cells were cultured for up to 4 weeks. Samples were taken every week and were stained with phycoerythrin-conjugated mouse anti-LMP1 monoclonal antibody to assay LMP1 positive population by flow cytometry. RESULTS: In EBV-infected cells, the LMP1-positive cell population reached 14% after 4 weeks of culture. CsA or H2O2 treatment promoted LMP1 positive population to 43% and 41% after 4 weeks of culture. Vitamin E (40 microM) completely inhibited LMP1 expression in EBV-infected cells and in CsA- or H2O2-treated cells. CONCLUSION: In agreement with our previous observation, CsA or H2O2 can promote EBV transformation of human B cells. This oxidative stress induced promotion of EBV transformation can be blocked by antioxidant Vitamin E. This finding may have future therapeutic implications for post-transplant lymphoproliferative disorder.

Antioxidants↗

Phi-LOG: a domain specific language for solving phylogenetic inference problems.

Domain experts think and reason at a high level of abstraction when they solve problems in their domain of expertise. We present the design and motivation behind a domain specific language called Phi-LOG to enable biologists (domain experts) to program solutions to phylogenetic inference problems at a very high level of abstraction. The implementation infrastructure (interpreter, compiler, debugger) for the DSL is automatically obtained through a software engineering framework based on Denotational Semantics and Logic Programming.

Computer Simulation↗

Cyclosporine directly causes oxidative stress and promotes Epstein-Barr virus transformation of human B cells.

BACKGROUND: We have previously shown that oxidative stress alone can promote transformation of human B cells infected with Epstein-Barr virus (EBV) in vitro, an accepted model mimicking posttransplant lymphoproliferative disorders (PTLDs). Our laboratory has investigated the direct effects of cyclosporine A (CyA) as an oxidant promoting B-cell transformation and we have proposed that CyA directly promotes B-cell transformation and that this effect can be blocked by antioxidants. METHODS: Human splenocytes were prepared by centrifugation and plating technique to provide a greater than 80% pure preparation of B cells that was used for the direct oxidative stress experiments. These cells were cocultured with CyA (500 ng/ml) and hydrogen peroxide (H(2)O(2), 0.15 mM) with or without antioxidant vitamin E (40 microM). Oxidative stress was evaluated by using a commercial lipid hydroperoxide (LPO) assay kit. In another set of three separate experiments, human B lymphocytes infected with EBV were cultured with CyA (500 ng/ml), H(2)O(2) (0.15 mM), and vitamin E (40 microM). B-Cell transformation by EBV was evaluated by counting colony number and [(3)H]-thymidine incorporation. RESULTS: At therapeutic concentrations, CyA (500 ng/mL) had an oxidative effect on human splenocytes in vitro, similar to the effect of H(2)O(2) (90 and 97% increases, respectively in LPO production over control P < 0.005), which was abrogated by the addition of vitamin E. Similarly, both CyA and H(2)O(2) promoted transformation of B cells infected with EBV(75 and 108% increases respectively in colony counts over control, P < 0.005). This effect was also blocked by vitamin E. CONCLUSIONS: Both CyA and H(2)O(2) have a direct oxidative effect on human B cells and cause promotion of EBV-induced transformation of B cells. These effects are blocked by the antioxidant vitamin E. These findings may have future therapeutic implications for PTLDs.

Antioxidants↗

Multiple renal arteries do not pose an impediment to the routine use of laparoscopic donor nephrectomy.

UNLABELLED: Since the first description by Ratner and collegues in 1996, laparoscopic live-donor nephrectomy is gaining wide acceptance in an attempt to minimize the donor morbidity, length of hospital stay and length of time to return to work. It is unknown whether multiple renal arteries pose additional problems with laparoscopic donor nephrectomy. In November 1998, our institution initiated laparoscopic donor nephrectomy program. In the ensuing 19 months, we performed 25 living donor renal transplants, 24 of them using laparoscopic donor nephrectomy. The left kidney was procured in all cases. Eight donor candidates (33%) had two or more renal arteries (two arteries in five patients and three patients). RESULTS: In six cases (25%), findings at surgery differed from the CT angography results (in four cases, CT angiogram reported fewer arteries than were found at surgery and in two cases it reported more). We found no significant differences in both donor outcomes and recipient, based on the presence or absence of multiple renal arteries. Among donor outcomes, we found equivalent results for donor warm ischemia time total donor operating time, and donor length of stay. For recipient outcomes, we found no significant differences between groups for the incidence of acute tubular necrosis (ATN), graft survival and most recent serum creatinine. In one case, we constructed two arteries into a single conduit on the backtable prior to transplantation. However, in most cases with multiple arteries, we implanted the arteries separately into the recipient external iliac artery. Based on this experience, we do not find the presence of multiple renal arteries to be a barrier to the successful use of kidney grafts procured by laparoscopic donor nephrectomy.

Adult↗

Using immersive VR as a tool for preoperative planning for minimally invasive donor nephrectomy.

For surgeons approaching minimally invasive donor nephrectomy it is important to identify variant anatomy preoperatively since this anatomy can vary significantly from patient to patient. The goal of this operation is to preserve the architecture and function of the organ so it can be transplanted and function successfully. The ability of the surgeon to navigate through an individual patient's anatomy in a virtual three-dimensional (3D) immersive environment augments understanding of anatomical relationships particular to that individual patient and facilitates conveying that information to other physicians and students. Utilizing automated 3D reconstruction of high contrast computed tomography (CT) scan files viewed in this way, surgeons reported a better preoperative understanding of the anatomical variations and encountered fewer surprises at the time of surgery.

Humans↗

Nonoperative management of bile leaks following liver transplantation.

UNLABELLED: The biliary anastomosis has been called 'the Achilles heel' of liver transplantation (RABKIN JM, ORLOFF SL, REED MH. Transplantation 1998: 65 [2]: 193; DAVIDSON BR, RAI R, KURZAWINSKI TR. Br J Surg 1999: 86 [4]: 447). Biliary complications after liver transplantation reportedly occur at an incidence of 20-30%, 10-15% as bile leaks. The management of bile leaks, especially early bile leaks, is controversial. In the present study, we report our experience with the management of bile leaks after liver transplantation. In this retrospective study, we reviewed 85 liver transplants over a 3-yr period. In 79, the biliary anastomosis was choledochocholedochostomy (CDCD) over a small-caliber T-tube, while choledochojejunostomy (CDJ) was used in 7. Over a mean follow up period of 13.5 months (median 10 months), 10 patients (12%) experienced a clinically significant bile leak within the first 3 months after liver transplantation. The early leaks, occurring within 1 month of transplant, were successfully managed by observation (DAVIDSON BR, RAI R, KURZAWINSKI TR. Br J Surg 1999: 86 [4]: 447) or endoscopic retrograde cholangiopancreatography (ERCP) and the placement of a biliary stent for a duration of 6-12 wk (RANDALL HB, WACHS ME, SOMBERG KA. Transplantation 1996: 61 [2]: 258). One of these resulted from accidental dislodgement of the T-tube on postoperative day 1; one resulted from necrosis at the CDCD anastomosis and required CDJ; the remaining four resulted from leaks along the T-tube track. One of the late leaks occurred following the planned removal of the T-tube at 3 months after liver transplantation; the other two were leaks along the T-tube track. All were successfully treated by ERCP and stent placement, though in one case, ERCP was initially unsuccessful because of the inability to advance a guidewire, necessitating a fluoroscopically aided guide wire placement during a mini laparotomy. ERCP was then successfully performed with the placement of a stent. [See table in text] CONCLUSIONS: Our experience indicates that most bile leaks after liver transplantation, including early leaks, can be successfully managed nonoperatively. Most will require intervention, but ERCP and stent placement are usually sufficient.

Adolescent↗

Piggyback technique and selective use of veno-venous bypass in adult orthotopic liver transplantation.

BACKGROUND: The piggyback technique (PT), with preservation of the cava, is being used more frequently in adult orthotopic liver transplantation (OLT). The advantages of PT include hemodynamic stability during the anhepatic phase without a large-volume fluid infusion and obviating the need for veno-venous bypass (VVB). At our center, we changed our practice in July 1997 from the standard technique (ST) of OLT with routine use of VVB to PT and selective use of VVB. The purpose of the present study was to analyze the results with the two different practices, ST-routine VVB versus PT-selective VVB. METHODS: Forty OLTs were performed during the period July 1995 July 1997 using ST-routine VVB (group I) and 36 during August 1997-December 1998 using PT-selective VVB (group II). The etiology of liver disease was similar in the two groups, with hepatitis C and alcoholic liver disease accounting for half of the patients in each group. The UNOS status, age, sex, and percentage of patients with previous upper abdominal surgery were also similar between the two groups. RESULTS: In the PT-selective VVB era (group II), 34/36 patients (94%) underwent OLT with PT and VVB was used for 8 (22%) patients. The decision to use VVB was elective for 3 patients (fulminant hepatic failure, 2; severe portal hypertension, 1) and urgent for 5 patients (hemodynamic instability during hepatectomy). The intraoperative use of packed red blood cells (PRBC) (mean +/- SD) was 15+/-12 units for group I and 9+/-8 units for group II (p = 0.023). Anastomosis time and total operating time (mean +/- SD) were 91 + 30 min and 9.5+/-3.2 h, respectively, for group I patients compared with 52+/-28 min and 7.6+/-1.6 h, respectively, for group II patients (p<0.0001 and 0.002, respectively). Median post-operative stays in the intensive care unit (ICU) and in the hospital were 5 and 17 d, respectively, for group I and 4 and 11 d, respectively, for group II (p = NS). Mean serum creatinine on day 3 was similar in the two groups. Median hospital charges for group I patients were $105439 compared with $91779 for group II patients (p = NS). The 1-year actuarial graft and patient survival rates were 78% and 82%, respectively, for group I, and 92% and 95%, respectively, for group II. CONCLUSIONS: PT is safe and can be performed in the majority of adult patients (>90%) undergoing OLT. With the routine application of the piggyback procedure, the use of VVB has been reduced to 20% of OLTs at our center. The practice of piggyback technique with the selective use of VVB is associated with shorter anhepatic phase and total operating time, lower blood product use, a trend towards shorter hospital length of stay, and reduced hospital charges compared with standard technique of OLT with routine use of VVB.

Female↗

Hospital charges following simultaneous kidney--pancreas transplantation: enteric drainage versus bladder drainage.

BACKGROUND: Enteric drainage (ED) is associated with reduced morbidity compared with bladder drainage (BD) after simultaneous kidney-pancreas transplantation (SKPT) and is becoming increasingly common (more than 50% of SKPTs done in the US in 1998 were performed with enteric drainage). Although several studies have reported the morbidity and graft survival of ED compared with BD previously, there are limited data available comparing the length of stay and hospital charges between these two drainage procedures. METHODS: Fourteen SKPTs were performed during the period January 1995 May 1998 using BD and 20 during June 1998-August 1999 using ED. Hospital charges analyzed included the following categories: pharmacy, inpatient room, laboratory, operating room, medical surgical supply, radiology/nuclear medicine, and miscellaneous. Organ acquisition charges and professional fees were not included in this analysis. RESULTS: The mean hospital stay for patients with ED was 7.8+/-2.2 d (range 5-12 d; median 7.5 d) compared with 15.9+/-7 d (range 8-38 d; median 15 d) for patients with BD (p = 0.002). The mean hospital charges during initial hospitalization for the ED group were $36 582+/-11 424 compared with $64 555+/-29 054 for the BD group (p = 0.005). There was a significant decrease in the charges relating to pharmacy, inpatient room, laboratory, radiology/nuclear medicine, and miscellaneous category in the ED group compared with the BD group, while the charges relating to operating room and medical-surgical supply were no different between the two groups. One-year actuarial kidney and pancreas graft survival rates were 83% and 93%, respectively, for the BD group and 90% and 80%, respectively, for the ED group (p = NS). CONCLUSIONS: SKPT patients with ED had a 43% reduction in hospital charges and equivalent pancreas and kidney graft survival rates compared with SKPT patients with BD. A shorter hospital stay and a reduction in pharmacy, radiology/nuclear medicine, and laboratory charges contributed to the decreased hospital charges in SKPT patients with ED.

Adult↗

Curcumin causes the growth arrest and apoptosis of B cell lymphoma by downregulation of egr-1, c-myc, bcl-XL, NF-kappa B, and p53.

It has been well known that curcumin is a powerful inhibitor of proliferation of several tumor cells. However, the molecular basis of the anti-proliferative effect of curcumin has not been investigated in detail. In this paper, we present evidence to show that curcumin inhibited proliferation of a variety of B lymphoma cells. At low concentrations curcumin inhibited the proliferation of BKS-2, an immature B cell lymphoma, more effectively than that of normal B lymphocytes and caused the apoptosis of BKS-2 cells in a dose- and time-dependent manner. Furthermore, curcumin downregulated the expression of survival genes egr-1, c-myc, and bcl-X(L) as well as the tumor suppressor gene p53 in B cells. In addition, NF-kappaB binding activity was also downregulated almost completely by curcumin. Stimulation with CpG oligonucleotides or anti-CD40 overcame growth inhibition induced by low concentrations of curcumin. Our results suggest that curcumin caused the growth arrest and apoptosis of BKS-2 immature B cell lymphoma by downregulation of growth and survival promoting genes.

Animals↗

Enhanced apoptosis mediates inhibition of EBV-transformed lymphoblastoid cell line proliferation by curcumin.

BACKGROUND: Epstein-Barr virus (EBV)-associated B-cell lymphomas occur more frequently in immunodeficient states such as organ transplantation and HIV infection. We have previously reported that B cell immortalization with EBV was promoted by cyclosporin A (CyA) and that curcumin (Cur), a natural phenol with known antioxidant and antitumor properties, blocked EBV-induced B cell immortalization. In the following experiments we show that Cur inhibits the proliferation of EBV-transformed lymphoblastoid cell lines (LCL) via enhanced apoptosis. METHODS: LCL were generated by infecting freshly isolated human B cells with EBV (B95-8) for 12 h and coculturing with predetermined optimal concentrations of CyA (500 ng/ml) for 4 weeks. LCL were then either frozen for future use or propagated for immediate experiments. These cells were then plated in 96-well plates with 20 microM Cur or 0.1% DMSO (vehicle control). The number of immortalized colonies/well, cell count, and (3)H uptake were used as an index of immortalization. To assess apoptosis rate LCL were cultured with 0.1% DMSO or Cur (20 microM) for 0, 18, and 42 h in culture flasks and then stained with MC540 and H33342, as markers for apoptosis, and analyzed by FACS. RESULTS: A profound inhibition of proliferation was seen in the LCL with 20 microM curcumin compared to 0.1% DMSO control. The colony count reduced from 34.5 +/- 3.4 to 0/well (P = 0.005), cell number reduced from 101,250 +/- 12,093 to 3750 +/- 1500/well (P = 0.002), and (3)H uptake reduced from 40,889 +/- 3669 to 70 +/- 5.2/well (P = 0.001). The apoptosis rate of LCL in the DMSO control at 24.07 and 16.87% increased significantly with 20 microM Cur to 76.4 and 95.1% at 18 and 42 h, respectively (P = 0.02). CONCLUSION: Cur is a potent inhibitor of EBV-transformed LCL. This effect appears to be mediated through enhanced apoptosis. A further investigation of this effect may be useful in prevention and therapy of B-cell lymphoma in immunodeficient patients.

Antineoplastic Agents↗

Curcumin blocks cyclosporine A-resistant CD28 costimulatory pathway of human T-cell proliferation.

INTRODUCTION: Curcumin (Cur) is a phenolic component of common spice, turmeric. We have reported earlier that it possesses antineoplastic and immunosuppressive properties in vitro. It has been reported that cyclosporine A (CyA), a commonly used immunosuppressant does not inhibit CD28 costimulatory pathway of T-cell activation. We hypothesized that Cur, a tyrosine kinase inhibitor, would block CyA-resistant CD28 costimulatory pathway of human T cell proliferation. MATERIALS AND METHODS: Human T-lymphocytes were isolated from healthy donors using gradient centrifugation and rosetting techniques. In four separate experiments T-cells were plated in triplicate in 96-well plates at a density of 2X105 cells/well. These cells were stimulated with 0.5 ng/ml phorbol myristate acetate (PMA) + 0.5 (g/ml anti-CD28 antibody (PMA-CD28 group) or 2.5 microgram/ml PHA (PHA group). Cur or CyA at varying concentrations (0.31, 0.625, 1.25, 2.5, 5, or 10 microgram/ml and 1.25, 2.5, 5, 10, 20, or 250 ng/ml, respectively) was added and cellular proliferation was measured by the uptake of [3H]thymidine and is reported (mean cpm/well(SD). Cells from the PMA-CD28 group that were treated with either curcumin or 0.4% DMSO (vehicle control for curcumin) were studied for evidence of apoptosis by staining with viable dyes MC540 and Hoechst 33342 and subsequently analyzed in the cell sorter. RESULTS: Cur caused a concentration-dependent inhibition of T-cell proliferation in the PMA-CD28 group (from 32775 +/- 3084 to 66 +/- 42 at 5.0 microgram/ml of cur) and PHA group (from 50956 +/- 5747 to 24 +/- 12 at 5.0 microgram/ml) with a calculated ED50 of 3.5 and 7.7, microM respectively. CyA inhibited T-cell proliferation in the PHA group with a calculated ED50 of 2.7 ng/ml but failed to block PMA + anti-CD28-stimulated T-cell proliferation even at 250 ng/ml. PMA-CD28 group cells treated with 10 microgram/ml curcumin showed a significantly increased apoptosis as compared to control (0.4% DMSO). CONCLUSION: Since Cur blocks the CyA-resistant PMA + anti-CD28 pathway of T-cell proliferation, it may have novel adjuvant immunosuppressive properties.

Anti-Inflammatory Agents, Non-Steroidal↗

The effect of curcumin on human B-cell immortalization by Epstein-Barr virus.

Cyclosporine is a commonly used immunosuppressant in solid-organ transplantation. It is, however, associated with an increased incidence of Epstein-Barr virus (EBV)induced post-transplant lymphoproliferative disorder (PTLD). In this study, human B lymphocytes isolated from healthy volunteers were immortalized in vitro with EBV. The effect of oxidative stress mediated by cyclosporine A or hydrogen peroxide on in vitro B cell immortalization was studied by coculturing immortalized B cells with cyclosporine A and hydrogen peroxide. Curcumin, a phenolic extract of the spice turmeric, was then used to observe its effect on this process. We found that in vitro B-cell immortalization with EBV was promoted by the oxidative stress induced by cyclosporine A and hydrogen peroxide, with the maximum effect seen at concentrations of 500 ng/ml and 100 microM, respectively. Curcumin blocked the B-cell immortalization in a dose-dependent fashion with nearly complete inhibition at 20 microM. We conclude that, because both hydrogen peroxide and cyclosporine A strongly promote in vitro B-cell immortalization with EBV (the putative process responsible for PTLD) and curcumin, an extract of a common spice is an effective inhibitor of this process; curcumin may be an effective adjunct in the prevention of PTLD in the patients undergoing therapy with cyclosporine A.

Anti-Inflammatory Agents, Non-Steroidal↗

The effect of acute hypocapnia on middle cerebral artery transcranial Doppler velocity during orthotopic liver transplantation: changes at reperfusion.

This study examines the effects of acute hypocapnia, instituted prior to reperfusion of the graft liver, on the middle cerebral artery (MCA) Doppler blood flow velocity response to reperfusion during orthotopic liver transplantation in humans. Seventeen patients with chronic liver disease underwent continuous, noninvasive Doppler imaging of the MCA. Hyperventilation to an end-tidal Pco2 of 25 +/- 1 mm Hg was associated with a decrease in mean MCA flow velocity (FVm) from 51.6 +/- 5.7 to 37.0 +/- 3.3 cm/s (P < 0.05). After reperfusion, the Paco2 increased from 32 +/- 1 to 40 +/- 1 mm Hg (P < 0.05), mean arterial pressure (MAP) decreased from 76 +/- 3 to 60 +/- 2 mm Hg, and the FVm increased from 37.0 +/- 3.3 to 54.0 +/- 4.7 cm/s (P < 0.05). FVm increased postreperfusion despite prior hyperventilation, decreased MAP, and abrupt increases in central venous and pulmonary artery pressure, but FVm did not exceed the prereperfusion level. In 10 of the 17 patients, the baseline FVm versus Paco2 response slopes and Paco2 measured postreperfusion were used to predict the FVm response to Paco2 after reperfusion. The slopes were similar to those reported for anesthetized patients without liver disease. Predicted FVm exceeded measured FVm in 9 of the 10 patients. We conclude that mild hyperventilation prior to reperfusion of the graft liver prevents FVm increases above prereperfusion baseline level.

Acute Disease↗

Gastric intramural pH as indicator of early allograft viability in orthotopic liver transplantation.

The determination of the viability of OLT grafts has relied upon metabolic tests of the liver, which take several hours to evaluate and therefore are only conclusive in most patients well into the postoperative period. Earlier diagnosis of graft failure or nonfunction would allow intraoperative reassessment of surgical technique and, in the case of graft failure, earlier planning for retransplantation. Since gastrointestinal mucosal ischemia is one of the earliest manifestations of impaired core tissue in the critically ill, a tonometric nasogastric tube (Tonomitor) was used in our patients to measure intramucosal gastric pH (pHi) during the preanhepatic (stage I), anhepatic (stage II), and neohepatic (stage III) phases of OLT in 35 patients as an indicator of graft liver function and viability. Based on the results of the pHi measurement 30 min after reperfusion during stage III, patients were divided into 2 groups using a pHi of 7.30 as the dividing point. Patients with a pHi equal or higher than 7.30 were assigned to group 1 (n = 24) and patients with a pHi lower than 7.30 were assigned to group 2 (n = 11). The pHi in group 1 patients averaged 7.37 +/- 0.5 30 min after reperfusion and throughout surgery. The pHi in group 2 patients was lower than that of the group 1 patients 30 min after reperfusion, 7.23 +/- 0.04 (P < 0.001). The pHi in 10 group 2 patients returned to normal within 3 hr after reperfusion and the pHi values for these patients were not significantly different from those of group 1 at 3 hr after reperfusion. The pHi in 1 group 2 patient remained lower than 7.30 and never returned to normal; this patient underwent retransplantation the following day. Utilizing the tonometric nasogastric tube to sample intramucosal pH allowed early detection of graft function and intermittent trending of pHi in patients with questionable graft function during the operative period. It also provided a means of assessing graft function independent of enzymatic criteria, which provide little information in the early phase of transplantation.

Adult↗