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Biomedical subjects

Alan W Hemming

Publications and source records attributed to Alan W Hemming.

At least 19 recordsLinked to original sources
PubMed2006

Ex vivo extended left hepatectomy with caval preservation, temporary portacaval shunt, and reconstruction of the right hepatic vein outflow using a reversed portal vein bifurcation graft.

Liver resections that require ex vivo techniques occur rarely, but when done are generally performed on veno-veno bypass to maintain venous return and decompress the portal circulation during the anhepatic phase of the procedure. We describe an ex vivo extended left hepatectomy that was performed with preservation of the inferior vena cava and the use of a temporary portacaval shunt to eliminate the need for veno-venous bypass. Ex vivo resection allowed reconstruction of right hepatic vein branches, using the patient's reversed portal vein bifurcation as a graft to provide venous outflow.

Adenocarcinoma↗
PubMed2006

Interleukin-6 and STAT3 protect the liver from hepatic ischemia and reperfusion injury during ischemic preconditioning.

BACKGROUND: Ischemic preconditioning has been shown to protect the liver from ischemia/reperfusion injury. We hypothesized that IL-6 directly modulates the protective effects of ischemic preconditioning. METHODS: Three weeks after undergoing splenic transposition, wild-type C57BL/6 and IL-6 null mice underwent 75 minutes of total hepatic ischemia with or without prior ischemic preconditioning (10 minutes of ischemia followed by 15 minutes of reperfusion). After reperfusion, serum ALT, serum IL-6, hepatic IL-6 mRNA, hepatic pSTAT3, and liver histology were evaluated. RESULTS: In wild-type mice, survival at 24 hours was greater in the preconditioned group compared with the non-preconditioned group (75% vs 40%, P<.05). In IL-6 null mice, however, ischemic preconditioning did not improve survival when compared with the non-preconditioned group. Preconditioning significantly reduced hepatocellular injury in wild-type mice (P<.05) when compared with IL-6 null animals. This protection was associated with significant increases in serum IL-6, hepatic IL-6 mRNA, and hepatic pSTAT3 levels (P<.05). The protective effects of ischemic preconditioning that correlated with significant increases in systemic IL-6, hepatic IL-6 mRNA abundance, and pSTAT3 levels, were not observed in IL-6 null mice. CONCLUSIONS: The protective effects of ischemic preconditioning during total hepatic ischemia/reperfusion injury are dependent on IL-6 signaling and are associated with increased phosphorylation of hepatic STAT3.

Alanine Transaminase↗
PubMed2006

Impact of implementation of the MELD scoring system on the prevalence and incidence of chronic renal disease following liver transplantation.

The implementation of the model for end-stage liver disease (MELD) score decreased mortality of those awaiting liver transplantation (LT); however, the impact of the MELD allocation system on the risk of chronic renal disease after LT remains unknown. We conducted a non-concurrent single-center cohort study of 174 patients undergoing LT at our center. We compared patients who underwent LT one year prior to MELD implementation (pre-MELD cohort) to those patients who underwent LT 1 year following MELD implementation (MELD cohort). All patients were followed for at least 2 years after LT. Stage 3 chronic renal disease (CRD-3) was defined by an estimated creatinine clearance (CL(Cr)) below 60 ml/min/1.73 m2, and stage 4 chronic renal disease (CRD-4) was defined by an estimated CL(Cr) below 30 mL/min/1.73 m2 according to the validated Modification of Diet and Renal Disease (MDRD) formula. Requirement of kidney transplantation and need for hemodialysis were also evaluated following LT. The pre-MELD cohort (n=97) and the MELD cohort (n=77) were comparable in baseline characteristics, prevalence of diabetes and hypertension, and immunosuppression. Mean calculated MELD score in the pre-MELD cohort was significantly lower than in the MELD cohort (16 vs. 19, P < 0.05). The estimated CL(Cr) at time of LT was lower in the MELD cohort compared with the pre-MELD cohort (75 vs. 95, P < 0.01). However, the incidence and prevalence of CRD-3 and CRD-4 at 6, 12, and 24 months after LT were comparable between the two cohorts. Need for kidney transplantation or hemodialysis after LT was comparable between the groups. In multivariate analysis, serum creatinine at LT was the only variable associated with the development of CRD-3 in the first 2 years after LT. In conclusion, the implementation of the MELD allocation system is not associated with increased mortality or occurrence of CRD-3 or CRD-4 in the first 2 years after LT.

Adolescent↗
PubMed2006

Portal vein resection for hilar cholangiocarcinoma.

Hilar cholangiocarcinoma remains a difficult challenge for the surgeon. Achieving negative surgical margins when resecting this relatively uncommon tumor is technically demanding as a result of the close proximity of the bile duct bifurcation to the vascular inflow of the liver. A recent advance in surgical treatment is the addition of portal vein resection to the procedure. Resection of the portal vein increases the number of patients offered a potentially curative approach but is technically more difficult and may increase the risk of the procedure. This study reviews the results of portal vein resection for hilar cholangiocarcinoma. Between 1998 and 2005, 60 patients underwent potentially curative resections of hilar cholangiocarcinoma. Mean patient age was 64 +/- 12 years (range, 24-85 years). Liver resections performed along with biliary resection included 49 trisegmentectomies (37 right, 12 left) and 10 lobectomies (8 left, 2 right). One patient had only the bile duct resected. Four patients also had simultaneous pancreaticoduodenectomy performed. Twenty-six patients required portal vein resection and reconstruction to achieve negative margins, 3 of which also required reconstruction of the hepatic artery. Operative mortality was 8 per cent with an overall complication rate of 40 per cent. Patients who underwent portal vein resection had an operative mortality of 4 per cent, which was not different from the 12 per cent mortality in patients who did not undergo portal vein resection (P = 0.39). There was no difference in actuarial patient survival between patients who underwent portal vein resection and those who did not (5-year survival 39 per cent vs. 41 per cent, P = not significant). Negative margins were achieved in 80 per cent of cases and were associated with improved survival (P < 0.01). Five-year actuarial survival in patients undergoing resection with negative margins was 45 per cent. There was no difference in margin status or long-term survival between those patients who underwent portal vein resection and those who did not. Only negative margin status was associated with improved survival by multivariate analysis. Portal vein resection for hilar cholangiocarcinoma is safe and allows a chance for long-term survival in otherwise unresectable patients.

Adult↗
PubMed2006

Presentation and management of gastrointestinal stromal tumors of the duodenum.

Duodenal gastrointestinal stromal tumors (GIST) have been described primarily in isolated case reports. In order to learn more about duodenal GIST, a retrospective review of patients with GIST managed at a single institution between 2000 and 2005 was conducted. Thirty-eight GIST of the stomach and small bowel were analyzed. Eight (21%) were duodenal GIST. The median size of duodenal GIST (6.0 cm) and small bowel GIST (6.3 cm) was larger than the median size of gastric GIST (3.0 cm). The most common presentation of duodenal GIST was bleeding (50%) which was similar to other small bowel GIST (49%) but different from gastric GIST which were most commonly an incidental finding (62%). Two patients (25%) with duodenal GIST had a history of neurofibromatosis. The duodenal GIST were located in the 2nd (n = 5, 63%) and 3rd portion of duodenum (n = 3, 37%). Seven of 8 patients underwent complete resection of duodenal GIST. Pancreaticoduodenectomy was the most common operation performed (n = 5); 2 patients were treated with partial duodenal resection. No patients undergoing pancreaticoduodenectomy (n = 5) were found to have lymph node metastases. No patients received neo-adjuvant or adjuvant therapy with Imatinib. Following resection, 2 patients have recurred (12 and 48 mo.), 4 patients are without disease (1, 6, 6, and 24 mo.), 1 patient died postoperatively. Duodenal GIST are relatively rare tumors that present most commonly with gastrointestinal bleeding. Duodenal GIST are associated with neurofibromatosis. Many duodenal GIST require pancreaticoduodenectomy for complete removal.

Adult↗
PubMed2005

Retroperitoneal soft tissue sarcoma.

The objective of the current study was to define the optimal treatment for patients with retroperitoneal soft tissue sarcomas (RPS). The authors conducted a review of the pertinent literature and found that the majority of patients had locally advanced RPS at the time of diagnosis. Surgery was the mainstay of treatment, and macroscopic total excision was feasible in approximately 50-67% of patients. The 5-year probability of local control was approximately 50%, and the likelihood of developing distant metastasis was approximately 20-30%. The 5-year survival rate was approximately 50%, and deaths due to recurrent RPS continued to occur after 5 years. Postoperative radiotherapy (RT) decreased the likelihood of local recurrence, although it demonstrated no impact on survival. Adjuvant chemotherapy had no proven efficacy. The factor that was found to have the greatest impact on the prognosis for patients with RPS was the ability to achieve a macroscopic total resection. The authors concluded that RPS usually is advanced at the time of diagnosis. The optimal treatment was complete resection. Most patients experienced recurrent disease after surgery, and the most common site of failure was local. Adjuvant RT reduced the risk of local recurrence, but its impact on survival was questionable.

Adolescent↗
PubMed2005

Endovascular stent graft repair of abdominal aortic aneurysms after liver transplantation.

It is estimated that 1.7% of orthotopic liver transplant recipients will develop abdominal aortic aneurysms (AAAs) after transplantation. It has been observed that these aneurysms expand faster in transplant recipients; therefore, aggressive surveillance for AAAs in transplant recipients is required. Endovascular aneurysm repair is rapidly becoming the standard of care, especially in patients with previous abdominal surgery and other significant comorbidities. This article describes our experience with AAAs in orthotopic liver transplant recipients treated successfully by endovascular stent graft repair.

Aged↗
PubMed2005

Left trisegmentectomy with reconstruction of segment 6 hepatic venous outflow using cryopreserved vein graft.

Liver resections that require hepatic vein reconstruction rarely occur. Options regarding venous reconstruction include primary end-to-end reconstruction, reimplantation into the vena cava, or the use of a variety of autologous or synthetic grafts. Cryopreserved vein grafts have recently become available for use. We describe a left trisegmentectomy with bile duct resection/reconstruction during which the segment 6 hepatic vein was reconstructed into the inferior vena cava using a cryopreserved vein graft.

Cryopreservation↗
PubMed2005

Surgical management of hilar cholangiocarcinoma.

OBJECTIVE: To assess the surgical management of hilar cholangiocarcinoma over a time period when liver resection was considered standard management. SUMMARY BACKGROUND DATA: Hilar cholangiocarcinoma remains a difficult challenge for surgeons. An advance in surgical treatment is the addition of liver resection to the procedure. However, liver resection in the setting of liver dysfunction caused by biliary obstruction can be associated with increased mortality. METHODS: Between 1997 and 2004, 80 patients with hilar cholangiocarcinoma having surgery were reviewed. Fifty-three patients had attempted curative resections, 14 patients had palliative bypasses, while 13 patients had findings that precluded any further intervention. Twenty-three patients required portal vein resection and reconstruction to achieve negative margins, 3 of which also required reconstruction of the hepatic artery. RESULTS: Patients undergoing resection had a 9% operative mortality, with morbidity of 40%. Patients who demonstrated lobar hypertrophy preoperatively due to tumor involvement of the contralateral liver or induced with portal vein embolization (PVE) had a significantly lower operative mortality than those patients without hypertrophy. Median overall survival in patients resected was 40 months, with 5-year survival of 35%. Negative margins were achieved in 80% of cases and were associated with improved survival. Five-year survival in patients undergoing resection with negative margins was 45%. CONCLUSION: Combined liver and bile-duct resection can be performed for hilar cholangiocarcinoma with acceptable mortality, though higher than that for liver resections performed for other indications. The use of PVE in cases where hypertrophy of the remnant liver has not occurred preoperatively may reduce the risk of operative mortality.

Adult↗
PubMed2005

Case of emphysematous pyelonephritis in a renal allograft.

Emphysematous pyelonephritis is a rare, but serious complication after renal transplantation. This is a case report of a 49-yr-old female who had a renal transplant for diabetic nephropathy. She presented to ER with about 1 wk history of right lower abdominal pain and fever 15 months after the transplant. She had gross hematuria and mental status changes just prior to presentation. A computed tomography (CT) scan of the abdomen showed extensive retroperitoneal and extraperitoneal air dissecting from the transplanted kidney in the right lower quadrant to the level of the mediastinum. There was air in the urinary bladder. These findings were highly suggestive of extensive emphysematous pyelonephritis. The patient was taken to the operating room emergently and underwent a transplant nephrectomy. Blood culture and urine culture were subsequently positive for Salmonella (serogroup O 6, 8 or C2). Initial blood culture also yielded Enterobacter cloacae. The patient was treated with imipenem, cefepime, flagyl, and diflucan empirically: this was later changed to complete a 6-wk course of ciprofloxacin upon discharge. Her hospital course was complicated by a urinary leak; she was discharged to home on day 21. This is the 12th reported case of emphysematous pyelonephritis occurred in a renal transplant recipient.

Emphysema↗
PubMed2005

The effects of renal transplantation on peripheral blood dendritic cells.

Recent advances allow accurate quantification of peripheral blood (PB) myeloid and plasmacytoid dendritic cell (DC) populations (mDC and pDC, respectively), although the response to renal transplantation (RT) remains unknown. Using flow cytometry, PBDC levels were quantified in patients with end stage renal disease (ESRD) undergoing RT. PBDC levels were significantly reduced in ESRD patients pre-RT compared to healthy controls, with further reduction noted immediately following a hemodialysis session. RT resulted in a dramatic decrease in both subsets, with a greater reduction of pDC levels. Both subset levels were significantly lower than in control patients undergoing abdominal surgery without RT. Subgroup analysis revealed significantly greater mDC reduction in RT recipients receiving anti-lymphocyte therapy, with preferential binding of antibody preparation to this subset. Samples from later time points revealed a gradual return of PBDC levels back to pre-transplant values concurrent with overall reduction of immunosuppression (IS). Finally, PBDC levels were significantly reduced in patients with BK virus nephropathy compared to recipients with stable graft function, despite lower overall IS. Our findings suggest that PBDC levels reflect the degree of IS in renal allograft recipients. Furthermore, PBDC monitoring may represent a novel strategy to predict important outcomes such as acute rejection, long-term graft loss and infectious complications.

Adult↗
PubMed2004

Sustained viral response to interferon and ribavirin in liver transplant recipients with recurrent hepatitis C.

Recurrent hepatitis C infection is an important cause of progressive fibrosis, cirrhosis, and graft loss following orthotopic liver transplantation. Treatment for posttransplant recurrence of hepatitis C with interferon-based therapy is difficult but results in loss of detectable virus in up to 30% of patients. However, the durability of viral clearance and the associated histologic response in this setting is unknown. The aim of this study was to determine whether viral loss in response to antiviral therapy is durable and associated with improvement in liver histology. All liver transplant recipients who received interferon-based treatment for recurrent hepatitis C virus (HCV) at the University of Florida from 1991 to 2002 were included in this study. Patients who lost detectable HCV after treatment with interferon alone or in combination with ribavirin were followed to assess the durability of viral response and its impact on liver histology. One hundred nineteen transplant recipients were treated with interferon or combination therapy. Twenty-nine (20 men, 9 women; mean age, 54 yrs [range, 42-74 yrs]) lost detectable HCV RNA and remained virus negative for at least 6 months after discontinuing therapy (sustained viral response[SVR]). The mean follow-up after discontinuing therapy was 24.7 months (range, 6-70 mos). Our study cohort included one patient with SVR following interferon monotherapy and 28 patients with SVR following combination therapy with interferon plus ribavirin. All patients remained HCV RNA negative (assessed by polymerase chain reaction or branched-DNA assay) during follow-up of up to 5 years. Liver histology assessed 2 years after treatment showed less inflammation compared with before treatment in 50% and showed no change in 38%. By 3 to 5 years post-treatment (n = 15 recipients), inflammation was reduced in 60% and remained unchanged in 33%. Fibrosis stage at 2 years improved by > or = 1 stage in 27 %, remained unchanged in 38 %, and worsened in 35% despite viral clearance. At 3 to 5 years, the fibrosis stage had improved in 67%, remained unchanged in 13%, and worsened in 20%. Both grade of inflammation and fibrosis stage improved by 3 to 5 years posttreatment compared with baseline histology (p < 0.05). In conclusion, loss of HCV after treatment of recurrent chronic hepatitis C with interferon and ribavirin is durable, and the durability of the SVR is associated with improvement in hepatic inflammation and regression of fibrosis.

Adult↗