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Biomedical subjects

L Ferrell

Publications and source records attributed to L Ferrell.

At least 19 recordsLinked to original sources

Expression of the coxsackievirus- and adenovirus receptor in gastrointestinal cancer correlates with tumor differentiation.

Modified adenoviruses represent a new approach to treatment of gastrointestinal cancer. However, their uptake by cells in many cases requires the major receptor for adenoviruses, the coxsackievirus and adenovirus receptor (CAR). Thus, lack of CAR expression is a potential cause of intrinsic resistance of tumor cells to this type of treatment. To evaluate this, we studied the localization of CAR protein in normal and malignant gastrointestinal tissues. In normal tissues, CAR was concentrated at sites of cell-cell interaction, in particular at the apico-lateral cellular surface. Expression was particularly strong around bile and pancreatic ducts, which is in agreement with CAR's physiological function as a tight-junction protein. In GI malignancies (esophageal, pancreatic, colorectal and liver cancer), expression of the receptor varied substantially. Loss of CAR expression at cell-cell junction was evident in many samples. A significant correlation between CAR expression and histological grade was found, with moderately to poorly differentiated tumors most frequently demonstrating loss or reduction of CAR expression. These data indicate that CAR expression is frequently altered in gastrointestinal malignancy, potentially reducing the efficacy of adenovirus-based therapies.

Adenoviridae↗

Increased engraftment and GVHD after in utero transplantation of MHC-mismatched bone marrow cells and CD80low, CD86(-) dendritic cells in a fetal mouse model.

BACKGROUND: Bone marrow transplantation (BMT) is the only known cure for a variety of inherited diseases and requires the administration of high doses of immunosuppressive and myeloablative therapy. Because the fetus is immunoincompetent early in gestation, in utero stem cell transplantation (IUT) could avoid the need for this toxic conditioning. A major limitation to date of IUT is the low level of engraftment and failure to induce tolerance. Dendritic cells (DC) are considered very potent antigen-presenting cells, but DC progenitors (pDC) are strongly tolerogenic. METHODS: We examined the effect of donor pDC on the degree of engraftment and tolerance induction after IUT. Bone marrow-derived pDC (CD80low, CD86-) from male C57BL/6 mice (H2b) were injected with and without donor bone marrow (BM) intraperitoneally into 13 to 15-day BALB/c (H2d) fetuses. Engraftment was determined by flow cytometry and quantitative polymerase chain reaction and tolerance by skin grafts and the mixed lymphocyte reaction. RESULTS: At 1-month posttransplant, mice that received BM+pDC showed a higher degree of engraftment (29+/-46%) than mice that received pDC-enriched cells or BM cells alone (0.11+/-0.70% and 1.71+/-1.66%, respectively, P<0.001). However, 5/19 recipients of BM+pDC died within 6 weeks; 4/5 had significant donor cell engraftment in blood and/or tissues. Also, these mice had evidence of graft-versus-host disease (GVHD). Two mice out of 15 long-term survivors in the BM+pDC group had virtually complete replacement of host with donor hematopoietic cells. Skin grafts and mixed lymphocyte reaction studies showed no durable tolerance induction other than in the two fully engrafted recipients of BM+pDC. CONCLUSIONS: These results suggest that donor pDC, along with donor BM, can have a significant impact on engraftment of MHC-mismatched donor cells associated with an increased incidence of GVHD. However, marrow-derived pDC do not result in an increase in tolerance induction in utero even when microchimerism is present.

Animals↗

Altered distribution of beta-catenin, and its binding proteins E-cadherin and APC, in ulcerative colitis-related colorectal cancers.

The beta-catenin pathway plays a central role in transcriptional signaling and cell-cell interactions in colonic epithelium. Alterations of the expression of beta-catenin, and its binding partners E-cadherin and the adenomatous polyposis coli protein (APC), are frequent events in sporadic colorectal cancer. Ulcerative colitis (UC)-related cancers originate in a field of chronic inflammation and therefore may have different alterations in the beta-catenin pathway than sporadic cancers. To test this hypothesis, expression and subcellular localization of beta-catenin, E-cadherin, and APC were detected by immunohistochemistry in paraffin sections from 33 UC-related and 42 sporadic colorectal cancers. Although beta-catenin and E-cadherin expression were predominantly limited to the lateral cell membrane in normal colonic epithelium, both tumor groups showed an overall shift from membranous to cytoplasmic expression for these proteins. An increase in nuclear localization of beta-catenin and a decrease in cytoplasmic APC expression also were seen in both cancer groups compared with normal epithelium. Abnormal beta-catenin expression was more closely linked to E-cadherin alterations in UC-related cancers than in sporadic cancers. In contrast, abnormal beta-catenin expression was more closely linked to APC alterations in sporadic cancers than in UC-related cancers. These data suggest that alterations of the beta-catenin pathway are important in both UC-related and sporadic colorectal cancers. However, differences in the expression patterns of beta-catenin, E-cadherin, and APC between UC-related and sporadic colorectal cancers suggest that the specific alterations in this pathway may differ in these two cancer groups.

Adenomatous Polyposis Coli Protein↗

Liver transplantation for hepatocellular carcinoma: expansion of the tumor size limits does not adversely impact survival.

The precise staging of hepatocellular carcinoma (HCC) based on the size and number of lesions that predict recurrence after orthotopic liver transplantation (OLT) has not been clearly established. We therefore analyzed the outcome of 70 consecutive patients with cirrhosis and HCC who underwent OLT over a 12-year period at our institution. Pathologic tumor staging of the explanted liver was based on the American Tumor Study Group modified Tumor-Node-Metastases (TNM) Staging Classification. Tumor recurrence occurred in 11.4% of patients after OLT. The Kaplan-Meier survival rates at 1 and 5 years were 91.3% and 72.4%, respectively, for patients with pT1 or pT2 HCC; and 82.4% and 74.1%, respectively, for pT3 tumors (P =.87). Patients with pT4 tumors, however, had a significantly worse 1-year survival of 33.3% (P =.0001). An alpha-fetoprotein (AFP) level > 1,000 ng/mL, total tumor diameter > 8 cm, age > or = 55 years and poorly differentiated histologic grade were also significant predictors for reduced survival in univariate analysis. Only pT4 stage and total tumor diameter remained statistically significant in multivariate analysis. Patients with HCC meeting the following criteria: solitary tumor < or = 6.5 cm, or < or = 3 nodules with the largest lesion < or = 4.5 cm and total tumor diameter < or = 8 cm, had survival rates of 90% and 75.2%, at 1 and 5 years, respectively, after OLT versus a 50% 1-year survival for patients with tumors exceeding these limits (P =.0005). We conclude that the current criteria for OLT based on tumor size may be modestly expanded while still preserving excellent survival after OLT.

Adult↗

Kidney morcellation in laparoscopic nephrectomy for tumor: recommendations for specimen sampling and pathologic tumor staging.

Laparoscopic nephrectomy is a novel approach for small renal tumors in selected patients; however, removal of the kidney through the small laparoscopic abdominal wall incision site requires the kidney to be morcellated into small fragments while still in situ. Morcellation presents two problems for the pathologist. First, guidelines for optimal sampling of morcellated fragments have not been described. Second, morcellation precludes complete pTNM tumor staging, in particular, tumor size, margins, and renal vein involvement. Based on our initial experience with 23 laparoscopic nephrectomies/nephroureterectomies (13 clinically suspected neoplasms, confirmed pathologically as renal cell carcinoma [RCC, n = 7], urothelial carcinoma of the renal pelvis [n = 3], angiomyolipoma [n = 1], and cystic nephroma [n = 1], and 10 clinically benign entities) and a conservative statistical model, we present a decision analysis model of various specimen sampling protocols that optimize cost, labor, or time to diagnosis (single vs sequential sampling). Using the tumor-to-kidney volume ratio (TKR), calculated from preoperative radiologic imaging and specimen gross weight, several specimen sampling algorithms were compared. For the average situation in which TKR is > or =0.15, the algorithm that most significantly optimizes cost and labor is one that initially samples 5% of the morcellated specimen. However, additional sampling may be required in one fourth of the cases. The optimal amount of sampled tissue may indeed be less than 5% because this assumes no suspicious tissue is grossly visible and in all our cases of RCC grossly visible tumor was identified. Additional nomograms for a spectrum of TKR, sampling success, and cost are presented to allow pathologists their own discretion in determining optimal sampling of the morcellated kidney. Tumor staging is severely limited by morcellation. Tumor size, renal capsule involvement, and renal vein involvement cannot be fully pathologically evaluated for RCC, whereas invasion cannot be definitively assessed for urothelial carcinoma of the renal pelvis. Knowledge of the radiologic features (lesion size, capsule, and vein involvement) is important in sampling and staging morcellated kidneys removed laparoscopically.

Algorithms↗

Severity of iron overload in patients with sickle cell disease receiving chronic red blood cell transfusion therapy.

Chronic transfusion therapy is being used more frequently to prevent and treat the complications of sickle cell disease. Previous studies have shown that the iron overload that results from such therapy in other patient populations is associated with significant morbidity and mortality. In this study we examined the extent of iron overload as well as the presence of liver injury and the predictive value of ferritin in estimating iron overload in children with sickle cell disease who receive chronic red blood cell transfusions. A poor correlation was observed between serum ferritin and the quantitative iron on liver biopsy (mean 13.68 +/- 6.64 mg/g dry weight; R = 0.350, P =.142). Quantitative iron was highly correlated with the months of transfusion (R = 0.795, P <.001), but serum ferritin at biopsy did not correlate with months of transfusion (R = 0.308, P =.200). Sixteen patients had abnormal biopsies showing mild to moderate changes on evaluation of inflammation or fibrosis. Liver iron was correlated with fibrosis score (R = 0.50, P =.042). No complications were associated with the liver biopsy. Our data suggest that, in patients with sickle cell disease, ferritin is a poor marker for accurately assessing iron overload and should not be used to direct long-term chelation therapy. Despite high levels of liver iron, the associated liver injury was not severe.

Anemia, Sickle Cell↗

HCV-related fibrosis progression following liver transplantation: increase in recent years.

BACKGROUND/AIMS: The natural history and predictors of HCV-related disease severity post-transplantation are uncertain. The aims of this study were to define the natural history of post-transplantation HCV infection by assessing the rate of fibrosis progression, to determine if the post-transplantation natural history differs from that observed pre-transplantation, and to identify predictors of post-transplantation disease progression. METHODS: Post-transplantation biopsies (mean: 3+/-1.6/patient) from 284 patients were scored according to histologic stage, using the method of Desmet et al. Change in fibrosis score (fibrosis progression/year) post-transplantation was used as the primary outcome. Predictors analyzed included viral factors (genotype and viral load at transplantation), patient demographics, year of transplantation, country of transplantation, pre-transplantation fibrosis progression, immunosuppression and laboratory data. RESULTS: There was a linear association between change in fibrosis score and time from transplantation, with a median rate of fibrosis progression per year of 0.3 (0.004-2.19/year). Using parametric time-to-event analysis, the expected median duration to cirrhosis was 10 years. The rate of post-transplantation fibrosis progression was significantly higher than pre-transplantation (0.2/year (0.09-0.8) p<0.0001), and higher in Spanish than US centers (0.48 (0.01-2.19) vs 0.28 (0.004-2.08); p=0.09) despite similar progression rates prior to transplantation. Variables independently associated with post-transplantation progression included year of transplantation (p=0.0001), race (p=0.02), number of methyl-prednisolone boluses (p=0.03), and HCV RNA levels at transplantation (p=0.01). CONCLUSIONS: HCV-related disease progression is accelerated in immunocompromised compared to immunocompetent patients, with a progressive increase in patients who have recently undergone liver transplantation. Changes in patient management post-transplantation over time and between transplant centers may account for the increase in fibrosis progression observed in recent years.

Adult↗

Effect of systemic cyclosporine on tumor recurrence after liver transplantation in a model of hepatocellular carcinoma.

BACKGROUND: Long-term results after liver transplantation for hepatocellular carcinoma have been disappointing, largely because of the high recurrence rate. It is controversial whether the immunosuppressed state of the recipient contributes to this recurrence rate. We have developed a model in the rat system to examine the effect of immunosuppression on tumor recurrence after transplantation, as well as to evaluate other treatment strategies to decrease the recurrence rate. METHODS: A 2-mm3 nodule of Morris hepatoma 3924a was implanted intrahepatically at day 0. At postimplant day 16, the animals underwent syngeneic orthotopic liver transplantation. Two treatment groups were established. Group I received saline injections subcutaneously for 2 weeks, while group II received subcutaneous cyclosporine injections at 3 mg/kg/day for 14 days. Animal survival, tumor recurrence rate, and sites of recurrence and number of pulmonary nodules were recorded. RESULTS: Overall survival rate was reduced in animals receiving cyclosporine. The mean survival time was 74.4 days (SEM 6.39 days) in saline-treated animals and 50.4 days (SEM 7.63 days) in the cyclosporine-treated animals. The proportion surviving in group 1 was 47% and in group 2 was 18%. This difference in survival was statistically significant (P=0.025). The incidence of pulmonary nodules was increased in the cyclosporine-treated animals, and tumor recurrence in extrapulmonary sites was seen only in the cyclosporine-treated animals. CONCLUSION: Results from this study suggest that cyclosporine has an adverse effect on tumor recurrence after transplantation. This model will be useful to further examine treatment strategies to improve the outcome of transplantation for hepatocellular carcinoma.

Animals↗

Evolution of hepatitis C virus quasispecies in patients with severe cholestatic hepatitis after liver transplantation.

Evolution of hepatitis C quasispecies may be one mechanism by which fibrosing cholestatic hepatitis develops after liver transplantation. In this study, we compared changes in quasispecies complexity and/or divergence in (1) hepatitis C-infected immunosuppressed transplant recipients and in immunocompetent controls; (2) transplant recipients with mild recurrence, and in those with the most severe form of posttransplantation recurrence. Quasispecies were measured in 12 hepatitis C-infected patients pretransplantation and posttransplantation (6 with mild and 6 with severe recurrence), and in 5 immunocompetent patients with similar follow-up, and characterized by heteroduplex mobility and sequence analysis of the hypervariable region. Although the number of variants (complexity) did not change with time in either group, there was a qualitative change in the variants with time (divergence) in immunocompromised, but not in immunocompetent patients. These changes were most marked with severe recurrence, and preceded the development of severe disease. Phylogenetic analysis confirmed that most posttransplantation variants were unrelated to those detected pretransplantation. These observations suggest that in the absence of immune suppression, there is minor evolution of quasispecies. With immune suppression, divergence of quasispecies is enhanced, resulting in selection/emergence of many new variants, particularly in those with fibrosing cholestatic hepatitis. Thus, quasispecies may influence disease progression in immune suppressed populations.

Cholestasis, Intrahepatic↗

Analysis of the reversibility of chronic liver allograft rejection implications for a staging schema.

In contrast to all other vascularized organ allografts, chronic rejection (CR) of the liver is potentially reversible. We therefore studied demographic, perioperative, biochemical, and histologic features associated with reversibility or progression to graft failure. Using very stringent clinical and histological criteria, we identified a subgroup of 23 of 916 patients receiving primary liver allografts with CR from the Liver Transplantation Database. Of these, 13 experienced graft failure as a result of CR, and 10 patients recovered to normal histology or liver injury test results. Male-to-female sex mismatch (p = 0.07), younger recipient age (p = 0.09), younger donor age (p = 0.06), white-to-white race match (p = 0.09), primary diagnosis of biliary atresia (p = 0.02), and cold ischemia time of more than 12 hours (p = 0.02) were associated with graft failure. Patients who eventually recovered from CR were more likely to have acute rejection within the first 2 weeks (70% vs 23%; p = 0.04), had a higher number of acute rejection episodes (p = 0.08), and were more likely to have been treated with OKT3 (90% vs 46%, p = 0.07). Although overlap existed in the histopathologic findings between the patients whose grafts failed and those who recovered, those patients who developed bile duct loss in more than 50% of the portal tracts (p < 0.01), severe (bridging) perivenular fibrosis (p = 0.05), and the presence of foam cell clusters (p = 0.06) were more likely to require retransplantation. In contrast to other solid organ allografts, CR of the liver is not an irreversible process. These findings can be used to understand the evolution of CR and to design a biologically correct and clinically relevant staging system.

Adolescent↗

Activity of high-dose cyclophosphamide in the treatment of childhood malignant gliomas.

Seventeen patients less than or equal to 20 years of age with newly diagnosed (n = 10) or recurrent (n = 7) malignant gliomas (anaplastic astrocytoma and glioblastoma multiforme) were treated with cyclophosphamide in association with hematopoietic cytokines (GM-CSF or G-CSF). Cyclophosphamide was given at a dose of 2 g/m2 daily for 2 days at 4-week intervals. Toxicity consisted of grade IV neutropenia and thrombocytopenia in 95% and 48% of cycles, respectively. There were no cyclophosphamide-related cardiac, pulmonary, or urothelial toxicities observed. Four of 10 patients with newly diagnosed disease demonstrated responses (three complete and one partial responses; one CR was only of 2 months duration). None of the seven patients with recurrent tumors demonstrated a response. We conclude that high-dose cyclophosphamide warrants further evaluation in children with newly diagnosed malignant glioma.

Adolescent↗

Chronic liver allograft rejection: a National Institute of Diabetes and Digestive and Kidney Diseases interinstitutional study analyzing the reliability of current criteria and proposal of an expanded definition. National Institute of Diabetes and Digestive and Kidney Diseases Liver Transplantation Database.

A study was conducted to assess the inter and intrarater agreement for the histopathologic features and diagnosis of chronic rejection (CR) and several other important causes of late liver allograft dysfunction. On two occasions, five pathologists, experienced with liver transplantation, reviewed a set of 49 slides representing a range of diagnoses, without knowledge of the clinical history or liver injury test results. The readings were correlated with the original histopathologic diagnosis, liver injury tests, and clinicopathologic follow-up. Assessment of biopsy adequacy (kappa = 0.69) and portal tract counts (kappa = 0.79) showed good to excellent intrarater agreement, whereas interrater agreement for these variables was moderate to good, respectively (kappa = 0.44 and 0.65). Likewise, the intrarater agreement for the diagnosis of CR (kappa = 0.68), hepatitis (kappa = 0.77), and obstructive cholangiopathy (kappa = 0.55) showed good to excellent agreement, whereas the interrater agreement for these same diagnoses ranged from fair to good (kappa = 0.58, 0.46, and 0.25, respectively). In 18 specimens, there was a near unanimous diagnosis of CR across both readings. These biopsies were obtained at a median of 7.1 months (range, 42 days to 4.9 years) after transplantation, and the average number of portal tracts was 8.4 (range, 4-15). Interestingly, only 13 of these 18 specimens showed bile duct loss in >50% of the portal triads; the remaining cases showed atrophy/pyknosis of the biliary epithelium in a majority of small bile ducts. Clinicopathologic correlation showed that these 18 biopsies were obtained from 16 grafts from 15 patients, 14 of whom ultimately required retransplantation or died of or with CR, whereas two of the grafts/patients recovered. A high rate of sensitivity (92%) and a somewhat lower, but acceptable, rate of specificity (71% to 80%) was found for the diagnosis of CR. Chronic rejection and other causes of late liver allograft dysfunction can be diagnosed reliably by a group of pathologists experienced with liver transplantation, and the diagnosis of CR correlates with clinical course and liver function abnormalities. Expanded criteria for the diagnosis of CR are presented, and potential problem areas for practicing pathologists are discussed.

Biopsy↗

Prognostic factors in adult soft-tissue sarcomas of the head and neck.

PURPOSE: The main objectives of this study were (a) to review the treatment results of primary head and neck soft-tissue sarcoma at our institution, (b) to identify important prognostic factors in local control and survival, and (c) to assess the efficacy of salvage therapy. METHODS AND MATERIALS: Sixty-five patients were treated at the University of California, San Francisco, between 1961 and 1993. Seventeen patients (27%) had low-grade, 10 (15%) had intermediate-grade, and 38 (58%) had high-grade sarcomas. Tumors were > 5 cm in 35 patients. Local management consisted of surgery alone in 14 patients (22%), surgery and radiotherapy in 40 (61%), and radiotherapy alone in 11 (17%) patients. The median follow-up was 64 months. RESULTS: The 5-year actuarial local control rate of the entire group was 66%. Tumor size and grade were important predictors for local control on multivariate analysis. The actuarial local control rate at 5 years was 92% for T1 vs. 40% for T2 primaries (p = 0.004), and 80% for Grade 1-2 vs. 48% for Grade 3 tumors (p = 0.01). None of the patients treated with radiotherapy alone with a dose of 50-65 Gy were controlled locally. Combined radiotherapy and surgery appeared to yield superior local control compared to surgery alone (77% vs. 59%); however, the difference was not statistically significant. The 5-year actuarial overall and cause-specific survivals were 56% and 60%, respectively. Unfavorable prognostic factors for cause-specific survival on multivariate analysis were age > 55 (p = 0.009), high tumor grade (p = 0.0002), inadequate surgery (p = 0.008), and positive surgical margins (p = 0.0009). In patients who underwent salvage therapy for treatment failure, the 5-year actuarial survival after salvage treatment was 26%. CONCLUSION: Tumor size and grade were important predictors for local control. Age, grade, adequacy of surgery, and status of surgical margins were significant prognostic factors for survival. There was a trend of improved local control with combined surgery and radiotherapy compared to either modality alone for high-risk patients. Radiotherapy alone with doses < or = 65 Gy was insufficient for control of gross disease. Aggressive salvage therapy was worthwhile in patients whose disease was uncontrolled after the initial treatment.

Adolescent↗

Antibody to the host cellular gene-derived epitope GOR-1 in liver transplant recipients with hepatitis C virus infection.

The presence of anti-GOR was determined in paired pre-orthotopic liver transplantation (pre-OLT) and post-OLT sera from 87 OLT patients with hepatitis C virus infection. Before OLT, 48/87 patients were seropositive for anti-GOR, but this marker had no relationship with the clinical and biochemical parameters, or viremia level. Anti-GOR was less commonly detected in patients infected with genotype 3a, compared with genotypes 1 and 2, which might be related to the less conserved nature of the proposed shared epitope (amino acid sequence 9-18) in genotype 3a isolates. After OLT (median follow-up 16 months), anti-GOR was detected in 31/87 patients and it had no correlation with the clinical and biochemical parameters, viremia level, histologic disease activity, and clinical outcome. Changes in anti-GOR status (before OLT versus after OLT) were also not related to any of the clinical parameters. Although anti-GOR is commonly detected in OLT patients infected with hepatitis C virus genotypes 1 and 2, it has no clinical or prognostic significance.

Adult↗

Pathological changes in yearly protocol liver biopsy specimens from healthy pediatric liver recipients.

Many centers perform biopsies on transplanted livers annually to assess allograft function because serum biochemical tests do not always correlate with histological findings. Although criteria exist for diagnosing acute cellular rejection, no similar criteria exist to describe the histopathological changes observed in the "normal" liver of an immunosuppressed but healthy child. The purpose of this study was to define the histopathological changes in the allografted livers of healthy children who have undergone transplantation and to evaluate them during long-term follow-up. One hundred fifty-eight yearly protocol liver biopsy specimens of 54 children who received transplants between January 1988 and March 1996 and at least 1 year of follow-up were reviewed, and the biopsy findings were correlated with those of serum tests of liver function performed concomitantly. Thirty-three biopsy specimens were excluded because serum transaminase levels were abnormal, the biopsy specimen was abnormal and diagnostic for a specific lesion, or follow-up showed progression of a specific disease process. In addition, time zero biopsy specimens from 21 of the 54 children were available for comparison. In the protocol biopsy specimens, portal and/or parenchymal mononuclear inflammatory infiltrates were frequent findings (48% and 25%, respectively). Other less common features were mild fibrosis (8%) and focal pericholangitis (6%). Findings in both protocol and time zero biopsy specimens included minimal to mild bile ductular proliferation (15% and 9.5%, respectively) and rare hepatocyte necrosis (1.6% and 5%). No yearly protocol biopsy specimens resulted in any patient benefit. Transplanted livers in immunosuppressed children who are clinically healthy and have normal transaminase levels commonly show histological changes consisting of scattered, mild to moderate, portal and/or parenchymal mononuclear infiltrates that are clinically insignificant. Yearly protocol biopsies in healthy pediatric recipients have been abandoned by the investigators after 3 years of follow-up.

Biopsy↗

Hepatitis C virus: quantitation and distribution in liver.

The optimal method for viral quantitation and the most appropriate site for determining viral load in patients with chronic hepatitis C virus (HCV) infection are unknown. We developed a method for measuring HCV RNA in the liver with the following features: 1) efficient extraction of RNA from tissue (89% of RNA recovered); 2) accurate amplification using branched DNA with strong concordance between a single sample tested on multiple occasions either in the same or in different runs; 3) good sensitivity (95%) and specificity (100%). HCV RNA was detected in as little as 2 mg of tissue, and viral load determined in a needle biopsy was representative of viral load in other parts of the liver. Within individual livers, 68% of the samples quantitated were within 1.5-fold of the geometric mean, and 95% were within 2.2-fold of the geometric mean. The mean ratio of virus in the liver and serum was 103, range 17.4-286. A delay of 30 minutes before freezing the liver tissue resulted in a reduction in the measured viral load in some, but not all instances. A sensitive, specific and reproducible method for quantitating HCV RNA in the liver has been developed. Measurement of viral load at one site was representative of viral load at other sites. While hepatic HCV RNA levels are consistently greater than serum levels, the ratio of liver of serum viral load varies widely. The clinical use of measurement of viral load in the liver remains to be defined.

Adult↗