Biomedical subjects

Andrew S Klein

Publications and source records attributed to Andrew S Klein.

25 records · Page 2Linked to original sources

PubMed2003

Surgical treatment of Budd-Chiari syndrome.

Shunting and transplantation are satisfactory methods of treating Budd-Chiari syndrome (BCS). Selection of treatment is based on the degree of hepatic injury (clinical settings), liver biopsy results, potential for parenchymal recovery, and pressure measurements. Shunting is recommended in cases of preserved hepatic function and architecture. In the presence of fulminant forms of BCS, in cases of established cirrhosis or frank fibrosis, or for patients with defined hepatic metabolic defects (e.g., protein C or protein S deficiency), liver transplantation is the treatment of choice. Nonsurgical alternatives, although encouraging, have limited long-term outcome results at the present time. In most cases of BCS, a thrombophilic disorder can be identified. However, it is important to note that postoperative vascular thrombosis has been identified in patients with BCS who do not have a definable hypercoagulable predisposition. It therefore is our practice to recommend early (<24 hours postoperatively) initiation of intravenous heparin therapy in all patients with BCS, who then undergo life-long anticoagulation with coumadin.

Budd-Chiari Syndrome↗

PubMed2003

Hepatic reticuloendothelial system dysfunction after ischemia-reperfusion: role of P-selectin-mediated neutrophil accumulation.

The relationship between hepatic ischemia-reperfusion (I-R) and subsequent injury through neutrophil accumulation is well described. Although alterations in reticuloendothelial system (RES) function (specifically Kupffer cell function) after I-R have been delineated, the degree to which discrete components of RES function (phagocytosis and killing) are independently modulated under these conditions has not been quantified. A hepatic segmental I-R model was established in mice, in which blood supply to the left lateral lobe of the liver was occluded for 45 minutes, the liver was reperfused, and the laparotomy incision was closed. Experimental animals were pretreated with either vinblastin (1.5 mg/kg) to induce neutropenia or anti-P-selectin monoclonal antibody (mAb; 50 microg/mice) 4 days and 5 minutes before ischemia, respectively. We previously reported that after intravenous injection of chromium 51 ((51)Cr) and iodine 125 ((125)I) double-labeled Escherichia coli, hepatic (51)Cr levels could be used to reliably quantify hepatic phagocytic clearance (HPC) of bacteria from blood, whereas the subsequent release of (125)I from the liver accurately paralleled hepatic bacterial killing efficiency (HKE). Using this double-label bacteria clearance assay, HPC and HKE were depressed after I-R, in association with hepatic neutrophil accumulation. Segmental I-R resulted in decreased HPC and HKE activity in both ischemic and nonischemic hepatic lobes. Depressions in HPC and HKE were attenuated by either vinblastin-induced neutropenia or blocking neutrophil adhesion to the hepatic endothelium with anti-P-selectin mAb. These findings support the hypothesis that I-R induces hepatic RES dysfunction, at least in part, through P-selectin-mediated neutrophil accumulation.

Animals↗

PubMed2003

Hepatic killing but not clearance of systemically circulating bacteria is dependent upon peripheral leukocytes via Mac-1 (CD11b/CD18).

The hepatic reticuloendothelial system (RES) is the primary mechanism for removing circulating bacteria from the systemic circulation. While Kupffer cells are important for this process, leukocytes appear to play a significant role as well. Hepatic leukocyte accumulation following ischemia/reperfusion or cytokine stimulation is well documented, but its contribution to phagocytic killing by the hepatic RES is not fully understood. We evaluated the role of leukocytes in general, and leukocyte-endothelial adhesion in particular, in hepatic RES function. This was done by inducing confirmed leukopenia with cyclophosphamide or by blocking leukocyte-endothelial adhesion molecules with specific blocking antibodies. Hepatic phagocytic clearance (HPC) and hepatic phagocytic killing (HKE) of systemically intravenously injected E. coli were assayed and quantitated by a validated dual isotope label technique. HPC among the various experimental groups and respective controls varied only slightly, with no statistically significant differences observed. Leukopenia or CD11b blockade each significantly decreased the HKE relative to the controls. Antibody blockade of certain other adhesion molecules had no significant effect on HKE (or HPC). The role of leukocytes in killing systemically circulating bacteria is an integral component of hepatic RES function. This capability of the leukocyte appears to be dependent, in part, on the adhesion molecule, Mac-1.

Animals↗

PubMed2003

Characterization of renal allograft rejection by urinary proteomic analysis.

OBJECTIVE: To develop a diagnostic method with no morbidity or mortality for the detection of acute renal transplant rejection. SUMMARY BACKGROUND DATA: Rejection constitutes the major impediment to the success of transplantation. Currently available methods, including clinical presentation and biochemical organ function parameters, often fail to detect rejection until late stages of progression. Renal biopsies have associated morbidity and mortality and provide only a limited sample of the organ. METHODS: Thirty-four urine samples were collected from 32 renal transplant patients at various stages posttransplantation. Samples were collected from 17 transplant recipients with acute rejection and 15 patients with no rejection. Samples from patients less than 4 days posttransplant were omitted from data analysis due to the presence of excessive inflammatory response proteins. Rejection status was confirmed by kidney biopsy. Specimens were analyzed in triplicate using SELDI mass spectrometry. The obtained spectra were subjected to bioinformatic analysis using ProPeak as well as CART (Classification and Regression Tree) algorithms to identify rejection biomarker candidates. These candidates were identified by their molecular weight and ranked by their ability to distinguish between nonrejection and rejection based on receiver operating characteristic (ROC) analysis. The candidates with the highest area under the ROC curve (AUC) exhibited the best diagnostic performance. RESULTS: The best candidate biomarkers demonstrated highly successful diagnostic performance: 6.5 kd (AUC = 0.839, P <.0001), 6.7 kd (AUC = 0.839, P <.0001), 6.6 kd (AUC = 0.807, P <.0001), 7.1 kd (AUC = 0.807, P <.0001), and 13.4 kd (AUC = 0.804, P <.0001). A separate analysis using the CART algorithm in the Ciphergen Biomarker Pattern Software correctly classified 91% of the 34 specimens in the training set, giving a sensitivity of 83% and specificity of 100% using two separate biomarker candidates at 10.0 kd and 3.4 kd. CONCLUSIONS: Biomarker candidates exist in urine that have the ability to distinguish between renal transplant patients with no rejection and those with acute rejection. These biomarker candidates are the basis for development of a noninvasive method of diagnosing acute rejection without the morbidity and mortality associated with needle biopsy. The combination of biomarkers into a panel for diagnosis leads to the possibility of enhanced diagnostic performance.

Acute Disease↗

PubMed2003

Juxta-caval hepatic angiomyolipoma masquerading as hepatocellular carcinoma.

Hepatic angiomyolipoma is an uncommon primary benign epithelial liver neoplasm. Most patients with angiomyolipomas are middle-aged women who commonly present with epigastric fullness or pain. Angiomyolipomas are tumors consisting of three tissue types: blood vessels, smooth muscle, and fat. Hepatic angiomyolipomas may be difficult to differentiate from other liver neoplasms by noninvasive imaging. We report a 58-year-old asymptomatic woman with a mass in the right lobe of the liver, found incidentally on routine abdominal sonography. Preoperative radiographic evaluation revealed a 6.5-cm hypervascular lesion abutting the inferior vena cava. Preoperative histologic study demonstrated an epithelial neoplasm suspicious for hepatocellular carcinoma. Metastatic workup was negative. At resection, the tumor was found to be an angiomyolipoma composed of lipoid, vascular and smooth muscle cells. Further staining was positive for HMB-45. Resection margins were negative. The woman had an uneventful recovery and was discharged on postoperative day seven. She currently remains well several months after her right hepatectomy.

Angiomyolipoma↗

PubMed2002

Outcome of orthotopic liver transplantation in patients with hepatitis C.

Recurrence of chronic hepatitis C (HCV) after orthotopic liver transplantation (OLT) is universal. The published studies suggest that the short-term outcome is good in these patients, but the long-term prognosis remains unclear. The purpose of this study was to evaluate the outcome of patients with HCV undergoing OLT in a single center and to analyze the risk factors associated with poor outcome. In this retrospective study, we evaluated the outcome of 58 OLT patients with proven HCV who underwent OLT between February 1990 and April 1997 at our institution. The median follow-up time was 36.9 months. Recurrent posttransplant HCV hepatitis was confirmed by liver biochemistry, histology, and persistent HCV RNA in the serum. The patient and graft survival of patients with HCV was compared to that of 42 primary biliary cirrhosis (PBC) and 41 primary sclerosing cholangitis (PSC) patients transplanted during the same period. Following OLT, biochemical evidence of recurrent HCV hepatitis was absent in 46%. Forty percent of patients had recurrent HCV hepatitis and 14% had clinical evidence of recurrent HCV. Thirty-one patients were on cyclosporine, 22 patients on tacrolimus, and 5 patients had cyclosporine switched to tacrolimus or vice versa. The recurrence rate of HCV chronic hepatitis was similar in patients who had cyclosporine (35.5%) or tacrolimus (45.5%) based immunosuppression. Eleven patients (19%) died and five patients (8.6%) were retransplanted for chronic rejection (two), mismatch (one), or primary graft nonfunction (two). The cumulative patient survival rates of one, three, and five years were 94.8%, 84.1%, and 62.2%, respectively. The severity of liver disease progressed with time; 8% of patients developed cirrhosis within two years. The survival rate did not show any relation between HCV recurrence and the type of immunosuppression. In conclusion, although the survival of patients with HCV was not statistically significant compared to those with PBC or PSC, there was a trend towards a lower five-year survival in HCV.

Cholangitis, Sclerosing↗

PubMedDate not supplied

Biliary obstruction reduces hepatic killing and phagocytic clearance of circulating microorganisms in rats.

Septic complications are common in patients with biliary obstruction. This is thought to be related, in part, to dysfunction of the hepatic reticuloendothelial system (RES). It has been reported that nearly 80% of circulating microorganisms are phagocytosed and killed within the liver and that clearance of circulating pathogens is significantly impaired in patients with jaundice. However, the effect of biliary obstruction specifically on phagocytic killing within the liver is less well described. Therefore this study was designed to quantify the effect of biliary obstruction, simultaneously and discriminately, on two important components of hepatic RES function (phagocytosis and phagocytic killing). Rats were divided into three experimental groups: control, sham, and jaundiced (common bile duct ligation). At 7, 10, 14, and 21 days after operation, E. coli labeled with both 125I and 51Cr were injected intravenously. Using the previously validated double-labeled in vivo E. coli technique, hepatic phagocytic clearance (HPC), hepatic killing efficiency (HKE), and net hepatic killing (NHK) were measured. Common bile duct ligation resulted in a significant decrease in the HPC of E. coli 10, 14, and 21 days postoperatively. Similarly, HKE was significantly decreased in jaundiced animals by postoperative day 10, but returned to baseline values by day 14. The net effect of these changes in HPC and HKE values were reflected in a significant reduction in NHK in jaundiced animals. Results of the present study suggest that obstructive jaundice impairs both phagocytosis and phagocytic killing within the liver. These findings may help to explain the susceptibility of patients with biliary tract obstruction to the morbidity and mortality of septic complications.

Animals↗