Biomedical subjects

Sang-Mo Kang

Publications and source records attributed to Sang-Mo Kang.

10 recordsLinked to original sources

PubMed2006

Targeted lymphoid homing of dendritic cells is required for prolongation of allograft survival.

Accumulating evidence that dendritic cells (DC) are important regulators of peripheral immune tolerance has led to the concept that donor-derived DC may be useful for inducing donor-specific transplantation tolerance. Although in vitro studies in this field have been encouraging, in vivo results have been inconsistent. Recent evidence has suggested a critical role of lymphoid organs in tolerance induction. In this study, we use a novel gene transduction technique to show that engineered expression of CCR7 on immature DC can markedly increase DC homing to lymphoid organs, leading to increased interaction with Ag-specific T cells. Moreover, we show that a single infusion of DC coexpressing CCR7 and the immunomodulatory molecule viral IL-10 (vIL-10) markedly prolongs cardiac allograft survival (mean survival time >100 days); importantly, DC expressing either vIL-10 alone or CCR7 alone was not effective. These results demonstrate an important paradigm for immune modulation using DC.

Animals↗

PubMed2005

More than 500 consecutive laparoscopic donor nephrectomies without conversion or repeated surgery.

HYPOTHESIS: Concern exists as to the safety of laparoscopic donor nephrectomy (LDN) compared with open donor nephrectomy. Reported complications of LDN include emergent conversion to an open procedure, repeated surgery for postoperative bleeding, and even death. We hypothesize that LDNs can be performed safely, with a complication rate comparable with that of open donor nephrectomies. DESIGN: Case series and review of the literature. SETTING: Tertiary care university hospital. PATIENTS: Five hundred thirty kidney donors. INTERVENTION: An LDN performed without hand assistance, with the kidney extracted through a low transverse incision. MAIN OUTCOME MEASURES: Mean operative time, requirement for transfusion, intraoperative complications, and postoperative complications. RESULTS: This series includes 84 right-sided donor nephrectomies, 86 donors with a body mass index greater than 30 (calculated as weight in kilograms divided by the square of height in meters), and 91 donors with complex vascular anatomy. Mean donor age was 40 years (range, 18-73 years), and mean +/- SD operative time was 196 +/- 43 minutes. The only conversion occurred early in the series, and there have been 525 subsequent cases without the need for conversion or repeated surgery. There were no donor deaths. Five donors (0.9%) required perioperative blood transfusions. Overall complication rate was 6.4%, including 14 minor wound infections, 2 bowel injuries, 1 case of prolonged ileus, 3 splenic injuries, 2 bladder infections, 1 bladder injury, 1 case of rhabdomyolysis, 1 case of pneumonia, and 2 thromboembolic events. CONCLUSION: This series demonstrates that LDN can be performed at least as safely as open donor nephrectomy, with minimal bleeding and few postoperative complications.

Adolescent↗

PubMed2005

End stage polycystic kidney disease: indications and timing of native nephrectomy relative to kidney transplantation.

PURPOSE: We evaluated the indications for and outcome of pre-transplant, concomitant and post-transplant native nephrectomy in patients with end stage polycystic kidney disease (PCKD). MATERIALS AND METHODS: The records of 32 patients were retrospectively reviewed using the electronic database at our institution. RESULTS: Between January 1992 and December 2002, 171 patients with end stage PCKD received a kidney transplant at University of California-San Francisco. A total of 32 patients (18.7%) underwent pre-transplant (7, group 1), concomitant (16, group 2) or post-transplant (9, group 3) native nephrectomy. Of these patients 25 underwent bilateral nephrectomy. Median followup was 18 months. Indications for nephrectomy were hematuria, a renal mass and chronic pain in group 1, lack of space in group 2 and urinary tract infection in group 3. Mean operative time +/- SEM was 231 +/- 14, 370 +/- 24 and 208 +/- 14 minutes in groups 1 to 3, respectively (p = 0.001). Mean intraoperative blood loss was 533 +/- 105, 573 +/- 155 and 522 +/- 181 ml in groups 1 to 3, respectively (p not significant). Two group 2 patients required blood transfusions. Postoperative complications requiring surgical intervention included wound dehiscence in group 1 and abdominal bleeding in group 3. Mean hospital stay was comparable among groups 1 to 3 at 7 +/- 0.7, 8.6 +/- 1.2 and 6.3 +/- 0.6 days, respectively (p not significant). At 3 months mean serum creatinine was not significantly different between groups 2 and 3 at 1.3 +/- 0.1 and 1.5 +/- 0.2 mg/dl, respectively. CONCLUSIONS: Unilateral or bilateral nephrectomy for PCKD at transplantation is safe in terms of postoperative patient morbidity and graft function. We perform concomitant native nephrectomy when indicated, preferably in recipients of living donor kidney transplants.

Adult↗

PubMed2005

BKV in simultaneous pancreas-kidney transplant recipients: a leading cause of renal graft loss in first 2 years post-transplant.

With the introduction of more potent immunosuppressive agents, rejection has decreased in simultaneous pancreas/kidney transplant (SPK) recipients. However, as a consequence, opportunistic infections have increased. The purpose of this report is to outline the course of SPK patients who developed polyomavirus-associated nephropathy (PVAN). A retrospective review of 146 consecutive SPK recipients from January 1, 1996 to December 31, 2002 was performed. Immunosuppression, rejection and development of PVAN were reviewed. Nine patients were identified. All received induction with either OKT3 or thymoglobulin. Immunosuppression included tacrolimus/cyclosporine, MMF/azathioprine and sirolimus/prednisone. Two patients were treated for kidney rejection prior to the diagnosis of PVAN. Time to diagnosis was an average of 359.3 days post-transplantation. Immunosuppression was decreased but five ultimately lost function. However, none developed pancreatic abnormalities as demonstrated by normal glucose and amylase. Two underwent renal retransplantation after PVAN diagnosis and both have normal kidney function. PVAN was the leading cause of renal loss in SPK patients in the first 2 years after transplantation and is a serious concern for SPK recipients. The pancreas, however, is spared from evidence of infection, and no pancreatic rejection occurred when immunosuppression was decreased.

Adult↗

PubMed2005

Laparoscopic procurement of kidneys with multiple renal arteries is associated with increased ureteral complications in the recipient.

This study investigates the effect of renal artery multiplicity on donor and recipient outcomes after laparoscopic donor nephrectomy. Three-hundred and sixty-one sequential procedures were performed over a 4-year period. Forty-nine involved accessory renal arteries; of these, 36 required revascularization and 13 were small polar vessels and ligated. The 312 remaining kidneys with single arteries served as controls. Study variables included operative times, blood loss, hospital stay, graft function and donor and recipient complications. Kidneys with multiple revascularized arteries had a longer mean warm ischemia time (35.3 vs. 29.2 min, p = 0.0003), and more ureteral complications (6/36 vs. 10/312, p = 0.0013) than single-artery controls. In contrast, ligation of a small superior accessory artery had no significant effect on donor operative time, blood loss, or complication rate while providing similar recipient graft function compared to single-artery controls. Renal artery number is important in selecting the appropriate kidney for laparoscopic procurement. Given the current excellent results with right-sided donor nephrectomy, kidneys with single arteries should be preferentially procured, irrespective of side.

Adult↗

PubMed2004

Laparoscopic right donor nephrectomy: a large single-center experience.

BACKGROUND: Laparoscopic procurement of right donor kidneys is frequently avoided or performed using hand-assist devices because of concerns regarding donor safety, adequate exposure, and vessel length. The present study describes the authors' large series of right donor nephrectomies performed laparoscopically without the use of hand ports or other manual assist devices. METHODS: The authors retrospectively analyzed all right laparoscopic donor nephrectomies performed at their center from November 1, 1999, to February 20, 2004. Study variables included operative times, blood loss, hospital stay, graft function, and donor and recipient complications. Left donor nephrectomies performed during the same period served as controls. RESULTS: Of 387 laparoscopic kidney procurements, 54 (14 %) were right nephrectomies. Blood loss, extraction times, length of stay, and overall complication rates were similar between right and left donor groups. The mean operative time in the right nephrectomy group was significantly shorter than in the left nephrectomy group (169 +/- 25 and 186 +/- 29 min, respectively; P = 0.003). Graft function 1 month after transplantation and the incidence of delayed graft function were similar in both groups. There was one graft loss caused by thrombosis in the left nephrectomy group; other graft-related complications in the recipients were similar in both groups. CONCLUSIONS: This large single-center experience demonstrates that laparoscopic right donor nephrectomy performed without hand-assist devices is safe and yields kidneys with excellent function. The authors conclude that selection of the appropriate kidney for donation using this approach can be based on the same criteria that have traditionally governed open donor nephrectomy.

Adult↗

PubMed2004

Congenital choledochal cysts in adults.

HYPOTHESIS: Excision of the extrahepatic portion of congenital choledochal cysts (CCs) avoids the risk of cancer. The standard classification scheme is out of date. DESIGN: Retrospective case series and literature review. SETTING: Tertiary care university hospital. PATIENTS: Thirty-eight adult patients diagnosed as having CC from 1990 to 2004. MAIN OUTCOME MEASURES: Clinical and radiographic imaging findings, operative treatment, pathologic features, and clinical outcome. RESULTS: Thirty-nine adult patients were treated for CCs (mean [SD] age at diagnosis, 31 [17] years, and mean [SD] age at surgery 37 [14] years). The primary report was abdominal pain (36 of 39 patients). Eight patients had cholangitis, 5 had jaundice, and 6 had pancreatitis. Radiographic imaging studies and operative findings showed that the abnormality predominantly involved the extrahepatic bile duct in 30 patients, the intrahepatic and extrahepatic bile ducts in 7 patients; and 2 were diverticula attached to the common bile duct. Surgical treatment in 29 (90%) of 31 patients with benign cysts (regardless of intrahepatic changes) consisted of resection of the enlarged extrahepatic bile duct and gallbladder and Roux-en-Y hepaticojejunostomy. Eight patients (21%) were initially seen with associated cancer (cholangiocarcinoma of the extrahepatic duct in 6; gallbladder cancer in 2). Seven of 8 patients had a prior diagnosis of CC but had undergone a drainage operation (3 patients), expectant treatment (3 patients), or incomplete excision (1patient). In none of the patients with cancer was surgery not curative. Nine patients had previously undergone a cystoduodenostomy and/or cystojejunostomy as children. Four of them had cancer on presentation as adults. There were no postoperative deaths. Cancer subsequently developed in no patient whose benign extrahepatic cyst was excised, regardless of the extent of enlargement of the intrahepatic bile duct. CONCLUSIONS: Congenital CCs consist principally of congenital dilation of the extrahepatic bile duct with a variable amount of intrahepatic involvement. We believe that the standard classification scheme is confusing, unsupported by evidence, misleading, and serves no purpose. The distinction between type I and type IV CCs has to be arbitrary, for the intrahepatic ducts were never completely normal. Although Caroli disease may resemble CCs morphologically, with respect to cause and clinical course, the 2 are unrelated. The other rare anomalies (gallbladderlike diverticula; choledochocele) are also unrelated to CC. Therefore, the term "congential choledochal cyst" should be exclusively reserved for congenital dilation of the extrahepatic and intrahepatic bile ducts apart from Caroli disease, and the other conditions should be referred to by their names, for example, choledochocele, and should no longer be thought of as subtypes of CC. Our data demonstrate once again a persistent tendency to recommend expectant treatment in patients without symptoms and the extreme risk of nonexcisional treatment. The entire extrahepatic biliary tree should be removed when CC is diagnosed whether or not symptoms are present. The outcome of that approach was excellent.

Adult↗

PubMed2003

Excellent short-term results with steroid-free maintenance immunosuppression in low-risk simultaneous pancreas-kidney transplantation.

HYPOTHESIS: Steroid avoidance is possible in simultaneous pancreas-kidney transplantation with the use of newer immunosuppressive agents and induction therapy. DESIGN: A retrospective consecutive case review. SETTING: A university tertiary referral center. PATIENTS: Medical records of 40 consecutive patients who underwent pancreas-kidney transplantation from November 2000 to July 2002 were reviewed. INTERVENTION: The immunosuppression protocol used in this series of patients consisted of Thymoglobulin induction combined with mycophenolate mofetil, tacrolimus, and sirolimus for maintenance immunosuppression. Steroids were used as pretreatment only, given with Thymoglobulin, and were typically discontinued by postoperative week 1. MAIN OUTCOME MEASURES: Graft and patient survival rates, rejection rates of the kidney or pancreas, infection rates, and surgical complication rates. RESULTS: Patient, kidney, and pancreas survival rates were 95.0%, 92.5%, and 87.5%, respectively. Biopsy-proven pancreas rejection rates at 1 and 3 months' posttransplantation were 2.5%. Kidney rejection rates at 1 and 3 months were 2.5%. Steroids were given only to patients with documented transplant rejection. Surgical and medical complications were no different from earlier protocols. CONCLUSIONS: Immunosuppression protocols that do not include maintenance steroids have shown minimal rejection in the first 3 months and equivalent patient and graft survival rates compared with protocols that use steroids. The potential beneficial long-term impact of steroid avoidance will require further study.

Adult↗

PubMed2003

Bioconversion of compactin into pravastatin by Streptomyces sp.

Streptomyces sp. Y-110, isolated from soil, modified compactin to pravastatin, a therapeutic agent for hypercholesterolemia. In a batch culture, the highest production of pravastatin was 340 mg l(-1) from 750 mg compactin l(-1) in 24 h. By intermittent feeding of compactin into the culture medium, both the compactin concentration and its conversion increased to 2000 mg l(-1) and 1000 mg pravastatin l(-1), respectively, with the conversion rate of 10 mg l(-1) h(-1). Continuous feeding of compactin increased production of pravastatin to 15 mg l(-1) h(-1).

Bioreactors↗

PubMed2003

Management of lymphoceles after renal transplantation: laparoscopic versus open drainage.

PURPOSE: Laparoscopic surgery has become widely accepted for the treatment of lymphoceles following kidney transplantation. In this single center study we retrospectively reviewed our results of the surgical management of post-transplant lymphoceles, assessing indication and outcome of laparoscopic versus open drainage. MATERIALS AND METHODS: The records of 60 patients who underwent surgical treatment for a symptomatic lymphocele following kidney transplantation or combined kidney/pancreas transplantation were retrospectively reviewed. RESULTS: Between 1995 and 2002, 1,836 patients received a kidney transplant at the University of California San Francisco. In 60 patients (3.3%) a symptomatic lymphocele developed and either laparoscopic (20) or open drainage (40) was completed. The conversion rate from laparoscopic to open drainage was 16.5%. The most common indications for open lymphocele drainage were noninfectious wound complications (13 patients) and a high risk of vessel or ureter injury (8) due to proximity of the lymphocele to hilar structures. Additional surgery on the graft was required in 5 patients. Intraoperative blood loss was significantly lower in the laparoscopy group. Median hospital stay was 1 day in the laparoscopy group versus 4 days in the open drainage group. No perioperative complications were observed in either group. After a median followup of 38 months, 2 patients in each treatment group had a symptomatic recurrence. CONCLUSIONS: Although both surgical approaches are safe and effective, laparoscopic drainage should remain the method of choice for the treatment of post-transplant lymphocele. However, open drainage should be performed in patients with wound complications and in those with a small lymphocele adjacent to vital renal structures.

Adult↗