T. Paul Singh

TNF-α, IL-6, IFN-γ, and IL-10 gene expression polymorphisms and the IL-4 receptor α-chain variant Q576R: Effects on renal allograft outcome

BACKGROUND There has been much interest recently in the effects of various cytokine gene expression polymorphisms on graft outcome. However, the results of these investigations reveal the outcomes to be organ-specific and center-specific. We sought to confirm and add to some of the earlier findings by studying the impact of tumor necrosis factor-alpha (TNF-alpha), interleukin-10 (IL-10), interferon-gamma (IFN-gamma), and interleukin-6 (IL-6) polymorphisms and the interleukin-4 (IL-4) receptor alpha-chain variant on posttransplant renal allograft outcome. METHOD TNF-alpha, IL-6, IFN-gamma, and IL-10 gene promoter region polymorphisms were assayed genotypically by PCR-SSP on 120 patients transplanted at the Albany Medical Center. These patients were also typed for the IL-4 receptor alpha-chain variant Q576R. RESULTS Producers of high levels of the proinflammatory cytokine TNF-alpha were found to be at increased risk for acute rejection episodes if the allograft was mismatched for the molecular products of the class II region of the human major histocompatibility complex (HLA-DR). Expression level polymorphisms of the IL-6, IFN-gamma, and IL-10 genes were not associated with acute rejection episodes, nor was the IL-4 receptor alpha-chain variant Q576R. CONCLUSIONS These data would suggest that the production of high levels of the cytokine TNF-alpha is especially detrimental to graft survival when the recipients T-helper lymphocytes are being activated by mismatched donor HLA-class II antigens. Typing all potential kidney recipients for TNF-alpha, and providing well-matched organs for high producers of this cytokines, may be expected to increase rejection-free graft survival in these patients.

The impact of obesity in renal transplantation: an analysis of paired cadaver kidneys

Background: Previous studies indicate that obesity is a risk factor in renal transplantation. However, these analyses did not control for variable donor factors that may strongly influence outcome. To control for donor variables such as age, cause of death, procurement techniques, preservation methods, cold ischaemia time and implantation technique, we analysed patient and graft survival in recipients of paired kidneys, derived from the same procurement procedure, preserved in the same manner, subjected to similar cold ischaemia time and implanted by the same surgical team. Between June 1992 and August 1999, 28 procurement procedures provided kidneys which were transplanted into one obese and one non‐obese recipient. Body mass index (BMI) was calculated as kg/m2. Recipients were classified as obese (BMI > 30) or non‐obese (BMI < 30). Immunotherapy for all recipients consisted of a triple therapy regimen of cyclosporine or prograf, azathioprine or cellcept, and prednisone. Patients with delayed graft function (DGF), defined as the need for dialysis within 72 h of the transplant procedure, were treated with anti‐thymocyte globulin (ATG) or thymoglobulin (TMG) induction for 5–7 d. The rate of DGF (7.1 versus 10.7%) and acute rejection (39.3 versus 35.7%) were similar in the obese and non‐obese recipient groups. Patient survival was similar at 1, 3 and 5 yr in both groups. In addition, graft survival was similar at 1 yr. However, a trend toward decreased medium‐term graft survival, which reached significance at 5 yr, was observed in the obese group. Furthermore, mean serum creatinine at 1 yr was higher in the obese group (2.0) compared with the non‐obese group ( 1 , 4 ) (p=0.12). This analysis of paired cadaver kidneys indicated that obesity is not a risk factor for DGF, acute rejection, and 1‐yr graft survival. However, a decreased medium‐ and long‐term graft survival trend, which reached statistical significance at 5 yr, was observed in obese recipients.

Complicated diverticulitis following renal transplantation

PURPOSE: Colonic perforations in renal transplant recipients have historically been associated with mortality rates as high as 50 to 100 percent. However, these previous series generally predate the use of cyclosporine-based immuno-suppressive protocols. METHODS: We retrospectively reviewed all patients who had undergone renal transplant from our institution and who developed complicated diverticulitis. Complicated diverticulitis was defined as diverticulitis involving free perforation, abscess, phlegmon, or fistula. Factors analyzed included the time interval since transplantation, use of cyclosporine, living-relatedvs. cadaveric donor, cause of renal failure, and presenting signs and symptoms. RESULTS: Between August 1969 and September 1996, 1,211 kidney transplants were performed in 1,137 patients. The first 388 patients (1969–1984) received prednisone and azathioprine, with cyclosporine added to the immunosuppressive regimen for the subsequent 823 recipients (1984–1996). Thirteen (1.1 percent) patients had episodes of complicated diverticulitis, occurring from 25 days to 14 years after transplant; all required surgical therapy. Clinical presentation was highly variable, ranging from asymptomatic pneumoperitoneum (2 patients) to generalized peritonitis. There was one perioperative mortality (7.7 percent). Patients with polycystic kidney disease as the cause of renal failure had a significantly higher rate of complicated diverticulitis. Specifically, patients with polycystic kidney disease (9 percent of the total transplant population) accounted for 46 percent of the cases of diverticulitis (P < 0.001, Fishers exact probability test). Neither treatment with cyclosporine nor donor source had a significant effect on the rate of diverticular complications (P=0.36 andP=0.99, respectively, Fishers exact probability test). CONCLUSION: Complicated diverticulitis following renal transplantation is rare, and the clinical presentation may be atypical in the immunosuppressed transplant recipient. Patients with polycystic kidney disease experience a significantly higher rate of complicated diverticulitis than do other transplant patients and, therefore, warrant aggressive diagnostic evaluation of even vague abdominal symptoms. In addition, pretransplant screening and prophylactic sigmoid resection in this high-risk population deserve consideration and further study.

Development of the VBLaST™: a virtual basic laparoscopic skill trainer

The FLS training tool box has now been adopted by the Society of Gastrointestinal Endoscopic Surgeons (SAGES) as an official training tool for minimally invasive procedures.

Failure of ganciclovir prophylaxis to completely eradicate CMV disease in renal transplant recipients treated with intense anti-rejection immunotherapy

Ganciclovir prophylactic regimens have been shown to be effective in renal transplant recipients at risk for primary (donor seropositive/recipient seronegative) and secondary (recipient seropositive) cytomegalovirus (CMV) disease. However, in addition to serologic factors, the type and intensity of the administered immunosuppression is a strong risk factor for CMV disease. Since January 1995, we have utilized a potent immunosuppressive protocol selectively in recipients at high risk for immunologic graft loss, defined as retransplant recipients, recipients with delayed graft function, non‐Caucasian recipients, and recipients suffering from acute rejection. 
Between January 1995 and December 1996, 110 consecutive renal transplants were performed in recipients who were either CMV seropositive or received an allograft from a CMV‐seropositive donor. All recipients received ganciclovir prophylactic therapy for 3 months post‐transplant. Group I (N=43) consisted of recipients at high‐immunologic risk for graft loss as defined above. These recipients were treated with an intense anti‐rejection immunotherapeutic regimen consisting of Cellcept, Neoral, and prednisone, with the frequent addition of antilymphocyte antibody therapies and intravenous methylprednisolone. The remaining 67 recipients (group II) were treated with a less intense immunotherapeutic regimen consisting of azathioprine, Neoral, and prednisone. The incidence and severity of CMV disease and the patient and allograft survival were compared. 
The incidence of CMV syndrome was greater in group I (28%) compared with group II (7%), and was statistically significant (p<0.05). The 1‐yr patient and graft survival were similar, 95 and 91%, respectively, for group I compared with 97 and 97%, respectively, for group II. 
These data suggest that 3 months of ganciclovir prophylactic therapy is significantly less effective for the prevention of CMV disease in renal transplant recipients at high risk for acute rejection treated with an intense immunotherapeutic regimen. These data suggest that more effective prevention of CMV disease in these high‐risk recipients will require the addition of other anti‐viral agents, such as immunoglobulin preparation to the prophylactic regimen.

Reverse Alignment “Mirror Image” Visualization as a Laparoscopic Training Tool Improves Task Performance

Reverse alignment (mirror image) visualization is a disconcerting situation occasionally faced during laparoscopic operations. This occurs when the camera faces back at the surgeon in the opposite direction from which the surgeon’s body and instruments are facing. Most surgeons will attempt to optimize trocar and camera placement to avoid this situation. The authors’ objective was to determine whether the intentional use of reverse alignment visualization during laparoscopic training would improve performance. A standard box trainer was configured for reverse alignment, and 34 medical students and junior surgical residents were randomized to train with either forward alignment (DIRECT) or reverse alignment (MIRROR) visualization. Enrollees were tested on both modalities before and after a 4-week structured training program specific to their modality. Student’s t test was used to determine differences in task performance between the 2 groups. Twenty-one participants completed the study (10 DIRECT, 11 MIRROR). There were no significant differences in performance time between DIRECT or MIRROR participants during forward or reverse alignment initial testing. At final testing, DIRECT participants had improved times only in forward alignment performance; they demonstrated no significant improvement in reverse alignment performance. MIRROR participants had significant time improvement in both forward and reverse alignment performance at final testing. Reverse alignment imaging for laparoscopic training improves task performance for both reverse alignment and forward alignment tasks. This may be translated into improved performance in the operating room when faced with reverse alignment situations. Minimal lab training can account for drastic adaptation to this environment.

Comparative Pharmacokinetics and Renal Effects of Cyclosporin A and Cyclosporin G in Renal Allograft Recipients

Cyclosporin G (CSG) has produced less nephrotoxicity than cyclosporin A (CSA) at equivalent doses in animal models. Conflicting results have been reported concerning differences in the pharmacokinetics of CSA and CSG in preclinical studies, and no data exist regarding the effect of steady‐state oral administration of CSG on renal function in transplant patients or CSG‐induced release of endothelin and nitric oxide (NO) in vivo. The objective of the study was to examine steady‐state pharmacokinetic profiles of adult renal allograft recipients receiving CSA and CSG in relation to concentrations of endothelin‐1 and NO2/NO3 in urine and plasma, creatinine clearance (Clcr), and urinary excretion of N‐acetyl‐β‐D‐glucosaminidase (NAG) 9 months after transplantation. Concentrations of CSA and CSG were measured in whole blood over a 12‐hour dose interval by both a monoclonal and polyclonal fluorescence polarization radioimmunoassay for CSA. A metabolite fraction was defined as the numerical difference between the levels obtained at each time point by both assays. Patient groups were defined as follows: group 1: initial CSA (n = 6); group 2: initial CSG (n = 7); group 3: five of the seven patients in group 2 taking CSG subsequently undergoing conversion to CSA; group 4: the same five patients in group 3 restudied 1 month after 1:1 dosage conversion to CSA; and group 5: CSA groups 1 and 4 combined (n = 11). In group 1, the metabolite fraction accounted for 32% to 54% of the total measurable drug concentration at each time point, whereas in group 2, the metabolite fraction accounted for at most 10% to 15% of the total drug levels measurable by polyclonal fluorescence polarization radioimmunoassay. Although there were no significant differences in any of the mean pharmacokinetic parameters between groups using monoclonal fluorescence polarization radioimmunoassay, the normalized area under the concentration—time curve (NAUC) value was less in four of five patients after conversion from CSG to CSA, with a more variable and delayed time to reach peak concentration (tmax) but equivalent apparent oral clearance (Clpo) values. Clcr was found to change significantly with time in groups 1 and 5 but not in group 2, with CSA producing a more profound and sustained decrease than CSG. Endothelin‐1 and NO2/NO3 levels in plasma and urine remained relatively constant after administration of both CSA and CSG, and there were no significant differences between groups 3 and 4 regarding mean endothelin‐1 and NO2/NO3 concentrations in plasma, urinary release of endothelin‐1 and NO2/NO3, and mean AUC of endothelin‐1 and AUC of NO2/NO3. However, monoclonal NAUC correlated significantly with total urinary endothelin‐1 within CSA groups 1 and 5 but not within CSG group 2. Metabolite NAUC correlated significantly with total urinary NAG within CSA group 1. Although limited by the small number of patients, this study suggests that 1) CSG may produce less of a reduction in Clcr over time after oral administration at steady state than does CSA, and 2) this beneficial effect of CSG may be in part due to decreased intrarenal release of endothelin‐1, as urinary excretion of endothelin‐1 seemed to correlate better with CSA than with CSG exposure.

Technique and outcomes of laparoscopic bulge repair after abdominal free flap reconstruction.

Bulges and hernias after abdominal free flap surgery are uncommon with rates ranging from as low as 0–36%. In the free flap breast reconstruction population, there are no clear guidelines or optimal strategies to treating postoperative bulges. We describe our minimally invasive technique and outcomes in managing bulge complications in abdominal free flap breast reconstruction patients.