Multi-organ, multi-lineage engraftment by a single bone marrow-derived stem cell

Purification of rare hematopoietic stem cell(s) (HSC) to homogeneity is required to study their self-renewal, differentiation, phenotype, and homing. Long-term repopulation (LTR) of irradiated hosts and serial transplantation to secondary hosts represent the gold standard for demonstrating self-renewal and differentiation, the defining properties of HSC. We show that rare cells that home to bone marrow can LTR primary and secondary recipients. During the homing, CD34 and SCA-1 expression increases uniquely on cells that home to marrow. These adult bone marrow cells have tremendous differentiative capacity as they can also differentiate into epithelial cells of the liver, lung, GI tract, and skin. This finding may contribute to clinical treatment of genetic disease or tissue repair.

Macrovesicular hepatic steatosis in living liver donors: use of CT for quantitative and qualitative assessment

PURPOSE

To determine prospectively the diagnostic performance of unenhanced computed tomography (CT) in the assessment of macrovesicular steatosis in potential donors for living donor liver transplantation by using same-day biopsy as a reference standard.

MATERIALS AND METHODS

Institutional review board approval and informed consent were obtained. A total of 154 candidates, including 104 men (mean age, 30.2 years +/- 10.3 [standard deviation]) and 50 women (mean age, 31.8 years +/- 11.2), underwent same-day unenhanced CT and ultrasonography-guided liver biopsy. Histologic degree of macrovesicular steatosis was determined. Three liver attenuation indices were derived: liver-to-spleen attenuation ratio (CT(L)(/S)), difference between hepatic and splenic attenuation (CT(L)(-S)), and blood-free hepatic parenchymal attenuation (CT(LP)). Regression equations were used to quantitatively estimate the degree of macrovesicular steatosis. Limits of agreement between estimated macrovesicular steatosis and the reference standard were calculated. Receiver operating characteristic analyses were used to determine the performance of each index for qualitative diagnosis of macrovesicular steatosis of 30% or greater. The cutoff value that provided a balance between sensitivity and specificity and the highest cutoff value that yielded 100% specificity were determined.

RESULTS

Limits of agreement were -14% to 14% for CT(L)(/S) and CT(L)(-S) and -13% to 13% for CT(LP). Performance in diagnosing macrovesicular steatosis of 30% or greater was not significantly different among indices (P > .05). Cutoff values of 0.9, -7, and 58 were determined for CT(L)(/S), CT(L)(-S), and CT(LP), respectively, and provided a balance between sensitivity and specificity. Cutoff values of 0.8, -9, and 42 were determined for CT(L)(/S), CT(L)(-S), and CT(LP), respectively, and yielded 100% specificity for all indices, with corresponding sensitivities of 82%, 82%, and 73% for CT(L)(/S), CT(L)(-S), and CT(LP), respectively.

CONCLUSION

Diagnostic performance of unenhanced CT for quantitative assessment of macrovesicular steatosis is not clinically acceptable. Unenhanced CT, however, provides high performance in qualitative diagnosis of macrovesicular steatosis of 30% or greater.

Genomic portrait of resectable hepatocellular carcinomas: implications of RB1 and FGF19 aberrations for patient stratification

Hepatic resection is the most curative treatment option for early-stage hepatocellular carcinoma, but is associated with a high recurrence rate, which exceeds 50% at 5 years after surgery. Understanding the genetic basis of hepatocellular carcinoma at surgically curable stages may enable the identification of new molecular biomarkers that accurately identify patients in need of additional early therapeutic interventions. Whole exome sequencing and copy number analysis was performed on 231 hepatocellular carcinomas (72% with hepatitis B viral infection) that were classified as early-stage hepatocellular carcinomas, candidates for surgical resection. Recurrent mutations were validated by Sanger sequencing. Unsupervised genomic analyses identified an association between specific genetic aberrations and postoperative clinical outcomes. Recurrent somatic mutations were identified in nine genes, including TP53, CTNNB1, AXIN1, RPS6KA3, and RB1. Recurrent homozygous deletions in FAM123A, RB1, and CDKN2A, and high-copy amplifications in MYC, RSPO2, CCND1, and FGF19 were detected. Pathway analyses of these genes revealed aberrations in the p53, Wnt, PIK3/Ras, cell cycle, and chromatin remodeling pathways. RB1 mutations were significantly associated with cancer-specific and recurrence-free survival after resection (multivariate P = 0.038 and P = 0.012, respectively). FGF19 amplifications, known to activate Wnt signaling, were mutually exclusive with CTNNB1 and AXIN1 mutations, and significantly associated with cirrhosis (P = 0.017).

CONCLUSION

RB1 mutations can be used as a prognostic molecular biomarker for resectable hepatocellular carcinoma. Further study is required to investigate the potential role of FGF19 amplification in driving hepatocarcinogenesis in patients with liver cirrhosis and to investigate the potential of anti-FGF19 treatment in these patients.

Lessons learned from 1,000 living donor liver transplantations in a single center: how to make living donations safe

Serious complications have occurred in a considerable proportion of living donors of liver transplants, but data from a single high-volume center has rarely been available. We analyzed the medical records of donors and recipients of the first 1,000 living donor liver transplants, performed at Asan Medical Center from December 1994 to June 2005, with a focus on donor safety. There were 107 pediatric and 893 adult transplants. The most common diagnoses were biliary atresia in pediatric recipients (63%) and hepatitis B-associated liver cirrhosis (80%) in adult recipients. Right lobe donors were strictly selected based on liver resection rate and steatosis. From 1,162 living donors, 588 right lobes, 6 extended right lobes, 7 right posterior segments, 464 left lobes, and 107 left lateral segments were obtained. Of these, 837 grafts were implanted singly, whereas 325, along with 1 cadaveric split graft, were implanted as dual grafts into 163 recipients. The 5-yr survival rates were 84.8% in pediatric recipients and 83.2% in adult recipients. There was no donor mortality, but 3.2% of donors experienced major complications. Until the end of 2001, the major donor complication rate was 6.7%, with most occurring in right liver donors. Since 2002, liver resection exceeding 65% of whole liver volume were avoided except for young donors with no hepatic steatosis, and the donor complication rate has been reduced to 1.3%. In conclusion, a majority of major living donor complications appear to be avoidable through the strict selection of living donor and graft type, intensive postoperative surveillance, and timely feedback of surgical techniques. Selection of right lobe graft should be very prudently considered if the donor right liver appears to be larger than 65% of the whole liver volume.

Expanded indication criteria of living donor liver transplantation for hepatocellular carcinoma at one large-volume center

The currently available indication criteria of living donor liver transplantation (LDLT) for patients with hepatocellular carcinoma (HCC) have high prognostic power but insufficient discriminatory power. On the basis of single-center results from 221 HCC patients undergoing LDLT, we modified the indication criteria for LDLT to expand recipient selection without increasing the posttransplant recurrence of HCC. Our expanded criteria, based on explant pathology, were largest tumor diameter < or = 5 cm, HCC number < or = 6, and no gross vascular invasion. One hundred eighty-six of the 221 HCC patients (84.2%) met our criteria, 10% and 5.5% more than those that met the Milan and University of California at San Francisco (UCSF) criteria, respectively. The overall 5-year patient survival rates were 76.0% and 44.5% within and beyond the Milan criteria, respectively; 75.9% and 36.4% within and beyond the UCSF criteria, respectively; and 76.3% and 18.9% within and beyond our expanded criteria, respectively. Although these 3 sets of criteria had similar prognostic power, our expanded criteria had the highest discriminatory power. Thus, these expanded criteria for LDLT eligibility of HCC patients broaden the indications for patient selection and can more accurately identify patients who will benefit from LDLT.

Congestion of right liver graft in living donor liver transplantation

BACKGROUND

Left liver graft from a small donor will not meet the metabolic demands of a larger adult recipient. One solution to this problem is to use a right liver graft without a middle hepatic vein (MHV). However, the need for drainage from the MHV tributaries has not yet been described.

METHODS

Five right liver grafts without a MHV were transplanted in patients including two hepatitis B virus-cirrhosis, two fulminant hepatic failure and one secondary biliary cirrhosis. The graft weight ranged from 650 to 1,000 g, corresponding to 48 to 83% of the standard liver volume of the recipients.

RESULTS

Two of five recipients were complicated with severe congestion of the right median sector immediately after reperfusion, followed by prolonged massive ascites and severe liver dysfunction. One of the patients died of sepsis with progressive hepatic dysfunction 20 days after the operation.

CONCLUSIONS

Preservation and reconstruction of the MHV tributaries is recommended to prevent congestion of the right liver graft without MHV.

Liver transplantation for "very early" intrahepatic cholangiocarcinoma: International retrospective study supporting a prospective assessment

The presence of an intrahepatic cholangiocarcinoma (iCCA) in a cirrhotic liver is a contraindication for liver transplantation in most centers worldwide. Recent investigations have shown that "very early" iCCA (single tumors ≤2 cm) may have acceptable results after liver transplantation. This study further evaluates this finding in a larger international multicenter cohort. The study group was composed of those patients who were transplanted for hepatocellular carcinoma or decompensated cirrhosis and found to have an iCCA at explant pathology. Patients were divided into those with "very early" iCCA and those with "advanced" disease (single tumor >2 cm or multifocal disease). Between January 2000 and December 2013, 81 patients were found to have an iCCA at explant; 33 had separate nodules of iCCA and hepatocellular carcinoma, and 48 had only iCCA (study group). Within the study group, 15/48 (31%) constituted the "very early" iCCA group and 33/48 (69%) the "advanced" group. There were no significant differences between groups in preoperative characteristics. At explant, the median size of the largest tumor was larger in the "advanced" group (3.1 [2.5-4.4] versus 1.6 [1.5-1.8]). After a median follow-up of 35 (13.5-76.4) months, the 1-year, 3-year, and 5-year cumulative risks of recurrence were, respectively, 7%, 18%, and 18% in the very early iCCA group versus 30%, 47%, and 61% in the advanced iCCA group, P = 0.01. The 1-year, 3-year, and 5-year actuarial survival rates were, respectively, 93%, 84%, and 65% in the very early iCCA group versus 79%, 50%, and 45% in the advanced iCCA group, P = 0.02.

CONCLUSION

Patients with cirrhosis and very early iCCA may become candidates for liver transplantation; a prospective multicenter clinical trial is needed to further confirm these results. (Hepatology 2016;64:1178-1188).

Association Between Expression Level of PD1 by Tumor-Infiltrating CD8+ T Cells and Features of Hepatocellular Carcinoma

BACKGROUND & AIMS

T-cell exhaustion, or an impaired capacity to secrete cytokines and proliferate with overexpression of immune checkpoint receptors, occurs during chronic viral infections but has also been observed in tumors, including hepatocellular carcinomas (HCCs). We investigated features of exhaustion in CD8⁺ T cells isolated from HCC specimens.

METHODS

We obtained HCC specimens, along with adjacent nontumor tissues and blood samples, from 90 patients who underwent surgical resection at Asan Medical Center (Seoul, Korea) from April 2016 through April 2018. Intrahepatic lymphocytes and tumor-infiltrating T cells were analyzed by flow cytometry. Tumor-infiltrating CD8⁺ T cells were sorted by flow cytometry into populations based on expression level of programmed cell death 1 (PDCD1 or PD1): PD1-high, PD1-intermediate, and PD1-negative. Sorted cells were analyzed by RNA sequencing. Proliferation and production of interferon gamma (IFNG) and tumor necrosis factor (TNF) by CD8⁺ T cells were measured in response to anti-CD3 and antibodies against immune checkpoint receptors including PD1, hepatitis A virus cellular receptor 2 (HAVCR2 or TIM3), lymphocyte activating 3 (LAG3), or isotype control. Tumor-associated antigen-specific CD8⁺ T cells were identified using HLA-A*0201 dextramers. PDL1 expression on tumor tissue was assessed by immunohistochemistry.

RESULTS

PD1-high, PD1-intermediate, and PD1-negative CD8⁺ T cells from HCCs had distinct gene expression profiles. PD1-high cells expressed higher levels of genes that regulate T-cell exhaustion than PD1-intermediate cells. PD1-high cells expressed TIM3 and LAG3, and low proportions of TCF1⁺, TBET^high/eomesodermin^low, and CD127⁺. PD1-high cells produced the lowest amounts of IFNG and TNF upon anti-CD3 stimulation. Differences in the PD1 expression patterns of CD8⁺ T cells led to the identification of 2 subgroups of HCCs: HCCs with a discrete population of PD1-high cells were more aggressive than HCCs without a discrete population of PD1-high cells. HCCs with a discrete population of PD1-high cells had higher levels of predictive biomarkers of response to anti-PD1 therapy. Incubation of CD8⁺ T cells from HCCs with a discrete population of PD1-high cells with antibodies against PD1 and TIM3 or LAG3 further restored proliferation and production of IFNG and TNF in response to anti-CD3.

CONCLUSIONS

We found HCC specimens to contain CD8⁺ T cells that express different levels of PD1. HCCs with a discrete population of PD1-high CD8⁺ T cells express TIM3 and/or LAG3 and produce low levels of IFNG and TNF in response to anti-CD3. Incubation of these cells with antibodies against PD1 and TIM3 or LAG3 further restore proliferation and production of cytokines; HCCs with a discrete population of PD1-high CD8⁺ T cells might be more susceptible to combined immune checkpoint blockade-based therapies.

Surgical treatment of hilar cholangiocarcinoma in the new era: the Asan experience

BACKGROUND/PURPOSE

Both curative resection and minimized in-hospital mortality offer the only chance of long-term survival in patients with hilar cholangiocarcinoma. The reported resectability rates for hilar cholangiocarcinoma have increased by virtue of combined major hepatectomy, but this procedure is technically demanding and still associated with a significant morbidity and mortality that must be carefully balanced against the chances of long-term survival.

METHODS

Between January 2001 and December 2008, 350 patients with hilar cholangiocarcinoma underwent exploration for the purpose of potentially curative resection, of whom 302 (86.3%) were resected in the Department of Hepato-Biliary Surgery and Liver Transplantation, Asan Medical Center, University of Ulsan College of Medicine. Combined hepatectomy was carried out in 268 (88.7%) of 302 resected patients. Major hemihepatectomy and parenchyma-preserving hepatectomy were performed in 257 and 11 patients, respectively. Portal vein resection was associated in 40 (14.9%) of 268 hepatectomized patients. To control preoperative cholangitis and reduce risk of postoperative hepatic failure, biliary decompression through endoscopic and/or percutaneous transhepatic drainage and portal vein embolization were preoperatively applied in 329 (94.0%) of 350 explored patients and in 91 (54.2%) of 168 extended hepatectomized patients (154 right hemihepatectomy, 9 right trisectionectomy, 5 left trisectionectomy), respectively. Liver transplantation was not performed as primary treatment for hilar cholangiocarcinoma.

RESULTS

There were 5 cases (1.7%) of in-hospital death after resection and 1 postoperative liver failure that was successfully treated with liver transplantation. Major complications were encountered in 23 patients (7.0%), and the overall morbidity rate was 43%. In 302 resections, 214 (70.9%) were curative resections (R0) and 88 (29.1%) were palliative resections (R1). The overall 1-, 3- and 5-year survival rates after resection, including in-hospital deaths, were 84.6, 50.7 and 47.3% in the R0 group and 69.9, 33.3 and 7.5% in the R1 group, respectively. The 5-year survival rate of extended hemihepatectomy of 36.4% was better than that of parenchyma-preserving hepatectomy at 10.5%. Two significant predictive factors adversely affecting survival after resection were lymph node metastasis and incurability of surgery (P < 0.001). Two patients with vascular involvement who underwent concomitant hepatic artery and portal vein reconstruction are alive after more than 3 years.

CONCLUSION

Preoperative biliary decompression and portal vein embolization enabled us to reduce in-hospital deaths associated with extended hepatectomy for hilar cholangiocarcinoma. Major hemihepatectomy offers an increased survival because of the higher possibility of curative resection than bile duct resection alone and parenchyma-preserving hepatectomy, but it still carries a certain mortality. Less extensive procedures can be conducted safely and are beneficial for aged patients in poor condition with a less advanced tumor stage if tumor-free resectional margins are obtained.

Kinetics and stoichiometry of light-induced proton release and uptake from purple membrane fragments, Halobacterium halobium cell envelopes, and phospholipid vesicles containing oriented purple membrane

We have used flash spectroscopy and pH indicator dyes to measure the kinetics and stoichiometry of light-induced proton release and uptake by purple membrane in aqueous suspension, in cell envelope vesicles and in lipid vesicles. The preferential orientation of bacteriorhodopsin in opposite directions in the envelope and lipid vesicles allows us to show that uptake of protons occurs on the cytoplasmic side of the purple membrane and release on the exterior side. In suspensions of isolated purple membrane, approximately one proton per cycling bacteriorhodopsin molecule appears transiently in the aqueous phase with a half-rise time of 0.8 ms and a half-decay time of 5.4 ms at 21degreesC. In cell envelope preparations which consist of vesicles with a preferential orientation of purple membrane, as in whole cells, and which pump protons out, the acidification of the medium has a half-rise time of less than 1.0 ms, which partially relaxes in approx. 10 ms and fully relaxes after many seconds. Phospholipid vesicles, which contain bacteriorhodopsin preferentially oriented in the opposite direction and pump protons in, show an alkalinization of the medium with a time constant of approximately 10 ms, preceded by a much smaller and faster acidification. The alkalinization relaxes over many seconds. The initial fast acidification in the lipid vesicles and the fast relaxation in the envelope vesicles are accounted for by the misoriented fractions of bacteriorhodopsin. The time constants of the main effects, acidification in the envelopes and alkalinization in the lipid vesicles correlate with the time constants for the release and uptake of protons in the isolated purple membrane, and therefore show that these must occur on the outer and inner surface respectively. The slow relaxation processes in the time range of several seconds must be attributed to the passive back diffusion of protons through the vesicle membrane.

Carbon partitioning to cellulose synthesis

This article discusses the importance and implications of regulating carbon partitioning to cellulose synthesis, the characteristics of cells that serve as major sinks for cellulose deposition, and enzymes that participate in the conversion of supplied carbon to cellulose. Cotton fibers, which deposit almost pure cellulose into their secondary cell walls, are referred to as a primary model system. For sucrose synthase, we discuss its proposed role in channeling UDP-Glc to cellulose synthase during secondary wall deposition, its gene family, its manipulation in transgenic plants, and mechanisms that may regulate its association with sites of polysaccharide synthesis. For cellulose synthase, we discuss the organization of the gene family and how protein diversity could relate to control of carbon partitioning to cellulose synthesis. Other enzymes emphasized include UDP-Glc pyrophosphorylase and sucrose phosphate synthase. New data are included on phosphorylation of cotton fiber sucrose synthase, possible regulation by Ca2+ of sucrose synthase localization, electron microscopic immunolocalization of sucrose synthase in cotton fibers, and phylogenetic relationships between cellulose synthase proteins, including three new ones identified in differentiating tracheary elements of Zinnia elegans. We develop a model for metabolism related to cellulose synthesis that implicates the changing intracellular localization of sucrose synthase as a molecular switch between survival metabolism and growth and/or differentiation processes involving cellulose synthesis.

Liver transplantation for adult patients with hepatocellular carcinoma in Korea: comparison between cadaveric donor and living donor liver transplantations

Current selection criteria of liver transplantation (LT) for patients with hepatocellular carcinoma (HCC) were derived from the outcomes of cadaveric donor LT (CDLT). We tried to assess the applicability of such criteria to living donor LT (LDLT) through a comparative study between CDLT and LDLT. We analyzed the outcomes of 312 HCC patients who underwent LT at 4 Korean institutions during 1992 to 2002. There were no gross differences of tumor characteristics between CDLT group (n = 75) and LDLT group (n = 237). Overall 3-year survival rate (3-YSR) was 61.1% after CDLT and 73.2% after LDLT including 38 cases of perioperative mortality. Comparison of HCC recurrence curves did not reveal any statistical difference between these 2 groups. Patient survival period till 50% mortality after HCC recurrence was 11 months after CDLT and 7 months after LDLT. Significant risk factors for HCC recurrence were alpha-fetoprotein level, tumor size, microvascular invasion, gross major vessel invasion, bilateral tumor distribution, and histologic differentiation in the LDLT group on univariate analysis, and tumor size, gross major vessel invasion, and histologic differentiation on multivariate analysis. Milan criteria were met in 70.4%: Their 3-YSR was 89.9% after CDLT and 91.4% after LDLT with exclusion of perioperative mortality. University of California San Francisco criteria were met in 77.7%: Their 3-YSR was 88.1% after CDLT and 90.6% after LDLT. In conclusion, we think that currently available selection criteria for HCC patients can be applicable to LDLT without change of prognostic power.

Efficacy of endoscopic and percutaneous treatments for biliary complications after cadaveric and living donor liver transplantation

BACKGROUND

Percutaneous transhepatic radiologic procedures as well as ERCP-based techniques have been used to treat biliary complications after liver transplantation. However, the efficacy of these treatments has not yet been clarified, especially for complications occurring after living donor liver transplantation.

METHODS

A retrospective study was performed to determine the frequency and types of the biliary complications after cadaveric donor liver transplantation and living donor liver transplantation. The success of ERCP and percutaneous transhepatic radiologic procedures was also evaluated. The choice of treatment approach, ERCP or percutaneous transhepatic radiologic procedures, depended on the type of biliary reconstruction and accessibility of the lesion.

RESULTS

Among 429 adult patients who underwent liver transplantation, 39 biliary complications developed in 25 patients (5.8%): biliary stricture (20), biliary stones (10), and bile leak (9). The frequency of biliary complications (5.8%; 6/103) after cadaveric donor liver transplantation was not significantly different compared with that after living donor liver transplantation (5.8%; 19/326). Success rates for treatment of biliary complications by means of ERCP and percutaneous transhepatic radiologic procedures were, respectively, 100% (11/11) and 78% (18/23). For endoscopically treated patients, balloon dilation alone for biliary strictures and nasobiliary tube placement alone for bile leaks resulted in complete resolution of the complication in, respectively, 67% (2/3) and 40% (2/5) without further intervention.

CONCLUSIONS

Transpapillary endoscopic and percutaneous transhepatic radiologic interventions are both effective therapies for biliary complications associated with liver transplantation. They are complementary approaches that help to avoid surgery for these complications.

Green-fluorescent protein as a new vital marker in plant cells

The green-fluorescent protein (GFP) from jellyfish Aequorea victoria has been used as a convenient new vital marker in various heterologous systems. However, it has been problematic to express GFP in higher eukaryotes, especially in higher plants. This paper reports that either a strong constitutive or a heat-shock promoter can direct the expression of GFP which is easily detectable in maize mesophyll protoplasts. In this single-cell system, bright green fluorescence emitted from GFP is visible when excited with UV or blue light even in the presence of blue fluorescence from the vacuole or the red chlorophyll autofluorescence from chloroplasts using a fluorescence microscope. No exogenous substrate, co-factor, or other gene product is required. GFP is very stable in plant cells and shows little photobleaching. Viable cells can be obtained after fluorescence-activated cell sorting based on GFP. The paper further reports that GFP can be detected in intact tissues after delivering the constructs into Arabidopsis leaf and root by microprojectile bombardment. The successful detection of GFP in plant cells relies on the use of a universal transcription enhancer from maize or the translation enhancer from tobacco mosaic virus (TMV) to boost the expression. This new reporter could be used to monitor gene expression, signal transduction, co-transfection, transformation, protein trafficking and localization, protein-protein interaction, cell separation and purification, and cell lineage in higher plants.

Long-term incidence, risk factors, and management of biliary complications after adult living donor liver transplantation

A considerable proportion of adult living donor liver transplantation (LDLT) recipients experience biliary complication (BC), but there are few reports regarding BC based on long-term studies of a large LDLT population. The present study examined BC incidence, risk factors and management using single-center data from 259 adult patients (225 right liver and 34 left liver grafts) between 2000 and 2002. The mean follow-up period was 46 +/- 14 months. Biliary reconstruction included single duct-to-duct anastomosis (DD, n = 141), double DD (n = 19), single hepaticojejunostomy (HJ, n = 67), double HJ (n = 28), and combined DD and HJ (n = 4). There were 12 episodes of anastomotic bile leak and 42 episodes of anastomotic stenosis in 50 recipients. Most leaks occurred within the first month, whereas stenosis occurred over 3 yr. Most stenoses were successfully treated using radiological intervention. Cumulative 1-, 3-, and 5-yr BC rates were 12.9%, 18.2%, and 20.2%, respectively. BC occurred much more frequently in right liver grafts compared to left liver grafts (P = 0.024). Stenosis-free survival curves for right liver graft recipients were similar for all reconstruction groups. When right liver graft recipients with single biliary reconstructions were grouped according to graft duct size and type of biliary reconstruction, DD involving a small-sized duct (less than 4 mm in diameter) was found to be a BC risk factor (P = 0.015), whereas HJ involving such duct sizes was not found to be associated with a higher risk (P = 0.471). In conclusion, close surveillance for BC appears necessary for at least the first 3 yr after LDLT. We found that most BC could be successfully controlled using radiological intervention. In terms of anastomotic stenosis risk, HJ appears a better choice than DD for right liver grafts involving ducts less than 4 mm in diameter.

Digital topological analysis of in vivo magnetic resonance microimages of trabecular bone reveals structural implications of osteoporosis

Osteoporosis is a disease characterized by bone volume loss and architectural deterioration. The majority of work aimed at evaluating the structural implications of the disease has been performed based on stereologic analysis of histomorphometric sections. Only recently noninvasive imaging methods have emerged that provide sufficient resolution to resolve individual trabeculae. In this article, we apply digital topological analysis (DTA) to magnetic resonance microimages (mu-MRI) of the radius obtained at 137 x 137 x 350 microm3 voxel size in a cohort of 79 women of widely varying bone mineral density (BMD) and vertebral deformity status. DTA is a new method that allows unambiguous determination of the three-dimensional (3D) topology of each voxel in a trabecular bone network. The analysis involves generation of a bone volume fraction map, which is subjected to subvoxel processing to alleviate partial volume blurring, followed by thresholding and skeletonization. The skeletonized images contain only surfaces, profiles, curves, and their mutual junctions as the remnants of trabecular plates and rods after skeletonization. DTA parameters were compared with integral BMD in the lumbar spine and femur as well as MR-derived bone volume fraction (BV/TV). Vertebral deformities were determined based on sagittal MRIs of the spine with a semiautomatic method and the number of deformities counted after threshold setting. DTA structural indices were found the strongest discriminators of subjects with deformities from those without deformities. Subjects with deformities (n = 29) had lower topological surface (SURF) density (p < 0.0005) and surface-to-curve ratio (SCR; a measure of the ratio of platelike to rodlike trabeculae; p < 0.0005) than those without. Profile interior (PI) density, a measure of intact trabecular rods, was also lower in the deformity group (p < 0.0001). These data provide the first in vivo evidence for the structural implications inherent in postmenopausal osteoporosis accompanying bone loss, that is, the conversion of trabecular plates to rods and disruption of rods due to repeated osteoclastic resorption.

Modified right liver graft from a living donor to prevent congestion

BACKGROUND

Right liver grafts without middle hepatic vein (MHV) drainage reconstruction resulted in severe congestion of the anterior segment (AS) in our early experience of adult-to-adult living donor liver transplantation (LDLT). However, a detailed strategy for preventing such congestion or the necessity of MHV reconstruction has not been discussed in LDLT using a right lobe graft.

METHODS

From July 1997 to February 1998, two of five right lobe grafts without MHV drainage reconstruction were complicated with severe congestion of the AS. Thereafter, 42 adult recipients who received right liver grafts with sizable MHV tributaries underwent the reconstruction of MHV drainage. All sizable (>5 mm in diameter) MHV tributaries were preserved during donor hepatectomy and were reconstructed with the recipient's autogenous interposition vein grafts at the bench surgery. The reconstructed vein grafts of this modified right lobe graft were anastomosed to the stump of the MHV and/or left hepatic vein of the recipient after graft revascularization.

RESULTS

Serial Doppler ultrasonography, which was regularly checked until 30 days posttransplant, revealed the patent interposition vein graft in 38 of 42 recipients (patency rate 90.5%). In these 38 recipients, no evidence of congestion in the AS was recognized on enhanced computed tomography, while providing enough functioning liver mass comparable to an extended right lobe graft. Also, congestion-related graft injury, such as an infarct of the AS, was not observed in these recipients.

CONCLUSIONS

Our early experience indicated the necessity of MHV drainage reconstruction in right lobe grafts, which do not have MHV trunk in certain instances. However, preoperatively, it is difficult to predict the degree of AS congestion of the right liver graft without MHV drainage reconstruction. We suggest aggressive reconstruction of MHV drainage tributaries of the AS, under the circumstances that sizable MHV tributaries are encountered, to prevent possible congestion-related complications.

Unenhanced CT for assessment of macrovesicular hepatic steatosis in living liver donors: comparison of visual grading with liver attenuation index

PURPOSE

To retrospectively compare the accuracy of visual grading and the liver attenuation index in the computed tomographic (CT) diagnosis of 30% or higher macrovesicular steatosis in living hepatic donors, by using histologic analysis as the reference standard.

MATERIALS AND METHODS

Institutional review board approval was obtained with waiver of informed consent. Of 703 consecutive hepatic donor candidates, 24 patients (22 men and two women; mean age +/- standard deviation, 36.3 years +/- 9.7) who had 30% or higher macrovesicular steatosis at histologic analysis and same-day CT with subsequent needle biopsy in the right hepatic lobe (at least two samples per patient) were evaluated. An age- and sex-matched control group of 24 subjects included those who had less than 30% macrovesicular steatosis but otherwise met the same criteria as the patient group. A diagnostically difficult setting was made by selecting those with the highest degree of macrovesicular steatosis when there were multiple control subjects matched for a particular subject in the patient group. Two independent radiologists assessed steatosis of the right hepatic lobe by using two methods: a five-point visual grading system that used attenuation comparison between the liver and hepatic vessels and the liver attenuation index (CT(L-S)), defined as hepatic attenuation minus splenic attenuation and calculated with region of interest measurements of hepatic attenuation. Interobserver agreement was assessed. Accuracy in the diagnosis of 30% or higher macrovesicular steatosis was compared by using a multireader, multicase receiver operating characteristic (ROC) analysis.

RESULTS

For visual grading, kappa = 0.905 (95% confidence interval [CI]: 0.834, 0.976). Intraclass correlation coefficient for CT(L-S) was 0.962 (95% CI: 0.893, 0.983). The area under the ROC curve of visual grading and CT(L-S) were 0.927 (95% CI: 0.822, 1) and 0.929 (95% CI: 0.874, 0.983), respectively, indicating no statistically significant difference (P = .975).

CONCLUSION

Both visual grading and CT(L-S) are highly reliable and similarly accurate in the diagnosis of 30% or higher macrovesicular steatosis in living hepatic donor candidates.

Enteric beta-defensin: molecular cloning and characterization of a gene with inducible intestinal epithelial cell expression associated with Cryptosporidium parvum infection

A growing body of evidence suggests that endogenous antibiotics contribute to the innate defense of mammalian mucosal surfaces. In the cow, beta-defensins constitute a large family of antibiotic peptides whose members have been previously isolated from the respiratory and oral mucosa, as well as circulating phagocytic cells. A novel bovine genomic clone with beta-defensin-related sequence [corrected] related to those of these alpha-defensins was isolated and characterized. The corresponding cDNA was isolated from a small intestinal library; its open reading frame predicts a deduced sequence of a novel beta-defensin, which we designate enteric beta-defensin (EBD). Northern blot analysis of a variety of bovine tissues revealed that EBD mRNA is highly expressed in the distal small intestine and colon, anatomic locations distinct from those for previously characterized beta-defensins. EBD mRNA was further localized by in situ hybridization to epithelial cells of the colon and small intestinal crypts. Infection of two calves with the intestinal parasite Cryptosporidium parvum induced 5- and 10-fold increases above control levels of EBD mRNA in intestinal tissues. An anchored-PCR strategy was used to identify other beta-defensin mRNAs expressed in the intestine. In addition to that of EBD, several low-abundance cDNAs which corresponded to other beta-defensin mRNAs were cloned. Most of these clones encoded previously characterized beta-defensins or closely related isoforms, but two encoded a previously uncharacterized prepro-beta-defensin. Northern blot evidence supported that all of these other beta-defensin genes are expressed at levels lower than that of the EBD gene in enteric tissue. Furthermore, some of these beta-defensin mRNAs were abundant in bone marrow, suggesting that in enteric tissue their expression may be in cells of hematopoietic origin. Extracts of small intestinal mucosa obtained from healthy cows have numerous active chromatographic fractions as determined by an antibacterial assay, and one peptide was partially purified. The peptide corresponded to one of the low-abundance cDNAs. This study provides evidence of beta-defensin expression in enteric tissue and that the mRNA encoding a major beta-defensin of enteric tissue, EBD, is inducibly expressed in enteric epithelial cells. These findings support the proposal that beta-defensins may contribute to host defense of enteric mucosa.

Innate-like Cytotoxic Function of Bystander-Activated CD8+ T Cells Is Associated with Liver Injury in Acute Hepatitis A

Acute hepatitis A (AHA) involves severe CD8⁺ T cell-mediated liver injury. Here we showed during AHA, CD8⁺ T cells specific to unrelated viruses became activated. Hepatitis A virus (HAV)-infected cells produced IL-15 that induced T cell receptor (TCR)-independent activation of memory CD8⁺ T cells. TCR-independent activation of non-HAV-specific CD8⁺ T cells were detected in patients, as indicated by NKG2D upregulation, a marker of TCR-independent T cell activation by IL-15. CD8⁺ T cells derived from AHA patients exerted innate-like cytotoxicity triggered by activating receptors NKG2D and NKp30 without TCR engagement. We demonstrated that the severity of liver injury in AHA patients correlated with the activation of HAV-unrelated virus-specific CD8⁺ T cells and the innate-like cytolytic activity of CD8⁺ T cells, but not the activation of HAV-specific T cells. Thus, host injury in AHA is associated with innate-like cytotoxicity of bystander-activated CD8⁺ T cells, a result with implications for acute viral diseases.

Cross-sectional study of osteopenia with quantitative MR imaging and bone densitometry

PURPOSE

To evaluation the cancellous bone-induced intravoxel spin dephasing rate (R2') and its relationship to bone mineral density and marrow fat and to examine these parameters as predictors of vertebral fracture status.

MATERIALS AND METHODS

R2' and R2, the rate constants for reversible and irreversible spin dephasing, and marrow fat fraction were measured in the lumbar vertebrae and proximal femur. One hundred thirty-nine subjects (mean age, 62.4 years +/- 11.4 [SD]; 33 men, 106 women) had spinal dual-energy x-ray absorptiometric bone mineral density (BMD) T scores ranging from +3 to -5. R2', BMD, and bone marrow composition as determinants of vertebral fracture status were examined.

RESULTS

Strongest single predictors of fracture status for BMD and R2' were the Ward triangle (r(2) = 0.48) and trochanter (r(2) = 0.37), respectively. Combined, the two parameters and sites increased fracture prediction (r(2) = 0. 62), whereas the combination of multiple BMD sites did not. Multivariate regression involving marrow fat fraction further improved fracture status prediction. R2' was correlated with BMD at all sites, although slopes differed by a factor of up to 2.5, which reflected differences in trabecular orientation relative to the static field. R2, the true transverse relaxation rate, was negatively correlated with marrow fat fraction. A non-age-related increase in marrow fat fraction in osteoporosis parallels earlier findings in animal models.

CONCLUSION

Cancellous bone marrow R2' measured in the proximal femur provides information, which, with BMD, improves prediction of vertebral fracture status.

CREB-binding protein and histone deacetylase regulate the transcriptional activity of Kaposi's sarcoma-associated herpesvirus open reading frame 50

Kaposi's sarcoma (KS)-associated herpesvirus (KSHV) open reading frame 50 (ORF50) encodes a viral transcriptional activator, which binds to the KSHV promoter and stimulates the transcription of viral early and late genes, thus activating the lytic cycle of KSHV. We report here that KSHV ORF50 binds to the cellular proteins CREB-binding protein (CBP) and histone deacetylase (HDAC) and these binding events modulate ORF50-activated viral transcription. Binding of ORF50 to CBP and HDAC activates and represses, respectively, ORF50-mediated viral transcription. KSHV ORF50 was shown to bind to the C/H3 domain and the C-terminal transcriptional activation domain of CBP, while CBP bound to the amino-terminal basic domain and the carboxyl-terminal transactivation domain of ORF50. The LXXLL motif within the transcriptional activation domain of ORF50 is reminiscent of the CBP-binding sequence found in nuclear receptor proteins. The adenovirus E1A protein, which also binds to the C/H3 domain of CBP, repressed the transcriptional activation activity of ORF50. The cellular protein c-Jun, which binds to the kinase-induced activation domain of ORF50, stimulated ORF50-mediated viral transcription. The HDAC1-interacting domain of ORF50 was shown to be a central proline-rich sequence. Our data provide a framework for delineating the regulatory mechanisms used by KSHV to modulate its transcription and replication through interaction with both histone acetyltransferases and HDACs.

MRI phenotype is associated with response to doxorubicin and cyclophosphamide neoadjuvant chemotherapy in stage III breast cancer

BACKGROUND

The preferred management for women with stage II or locally advanced breast cancer (LABC) is neoadjuvant chemotherapy. Pathologic response to chemotherapy has been shown to be an excellent predictor of outcome. Surrogates that can predict pathologic response and outcome will fuel future changes in management. Magnetic resonance imaging (MRI) demonstrates that patients with LABC have distinct tumor patterns. We investigated whether or not these patterns predict response to therapy.

METHODS

Thirty-three women who received neoadjuvant doxorubicin and cyclophosphamide chemotherapy for 4 cycles and serial breast MRI scans before and after therapy were evaluated for this study. Response to therapy was measured by change in the longest diameter on the MRI.

RESULTS

Five distinct imaging patterns were identified: circumscribed mass, nodular tissue infiltration diffuse tissue infiltration, patchy enhancement, and septal spread. The likelihood of a partial or complete response as measured by change in longest diameter was 77%, 37.5%, 20%, and 25%, respectively.

CONCLUSIONS

MRI affords three-dimensional characterization of tumors and has revealed distinct patterns of tumor presentation that predict response. A multisite trial is being planned to combine imaging and genetic information in an effort to better understand and predict response and, ultimately, to tailor therapy and direct the use of novel agents.

Unfolding and refolding of a purified precursor protein during import into isolated mitochondria

A purified mitochondrial precursor protein unfolds to a protease-sensitive conformation at the surface of isolated mitochondria before being imported into the organelles. This unfolding is stimulated by a potential across the mitochondrial inner membrane, but does not require ATP. In contrast, import of the surface-bound unfolded precursor requires ATP, but no potential; it is accompanied by a refolding inside the mitochondria.

Cancellous bone volume and structure in the forearm: noninvasive assessment with MR microimaging and image processing

PURPOSE

To develop and apply a method for the derivation of cancellous bone architectural parameters from in vivo magnetic resonance (MR) images of the distal radius and to evaluate these parameters as predictors of vertebral fracture status in osteopenia.

MATERIALS AND METHODS

MR images (137 x 137 x 500-micron3 voxel size) were acquired with a three-dimensional partial flip-angle spin-echo pulse sequence in the distal radius of 36 women. Subjects were classified as healthy or with osteoporosis on the basis of vertebral deformity and bone mineral density (BMD). Images rated as of adequate quality in 20 subjects were processed with a method that is applicable in the limited spatial resolution regime. The method relies on histogram deconvolution to obviate binary segmentation. Cancellous bone structure was treated as a quasi-regular lattice and analyzed with spatial autocorrelation, yielding parameters that quantify intertrabecular spacing, contiguity, and a measure of longitudinal alignment called tubularity.

RESULTS

Whereas neither BMD nor any of the structural parameters individually correlated significantly with vertebral deformity fraction, a simple function that involved tubularity and longitudinal spacing predicted deformity fraction well (r = .78, P < .005).

CONCLUSION

Histomorphometric parameters characterizing cancellous bone in the distal radius can be derived from in vivo MR microimages and are predictive of vertebral deformity.