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.

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).

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.

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.

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.

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.

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.

Timely translation during the mouse oocyte-to-embryo transition

In the mouse, completion of oocyte maturation and the initiation of preimplantation development occur during transcriptional silence and depend on the presence and translation of stored mRNAs transcribed in the growing oocyte. The Spin gene has three transcripts, each with an identical open reading frame and a different 3′ untranslated region (UTR). (Beta)-galactosidase-tagged reporter transcripts containing each of the different Spin 3′UTRs were injected into oocytes and zygotes and (beta)-galactosidase activity was monitored. Results from these experiments suggest that differential polyadenylation and translation occurs at two critical points in the oocyte-to-embryo transition - upon oocyte maturation and fertilization - and is dependent on sequences in the 3′UTR. The stability and mobility shifts of ten other maternal transcripts were monitored by reprobing a northern blot of oocytes and embryos collected at 12 hour intervals after fertilization. Some are more stable than others and the upward mobility shift associated with polyadenylation correlates with the presence of cytoplasmic polyadenylation elements (CPEs) within about 120 nucleotides of the nuclear polyadenylation signal. A survey of the 3′ UTRs of expressed sequence tag clusters from a mouse 2-cell stage cDNA library indicates that about one third contain CPEs. We suggest that differential transcript stability and a translational control program can supply the diversity of protein products necessary for oocyte maturation and the initiation of development.

One hundred and eleven liver resections for hilar bile duct cancer

A positive correlation between absence of residual tumor at resection margins and long-term survival in the treatment of hilar bile duct carcinoma has encouraged some surgeons to use a more radical approach, including liver/portal vein resection and combined pancreatoduodenectomy. However, if liver resection is associated with significant morbidity and mortality, it may not produce any overall benefit. This review was undertaken in an attempt to determine whether liver resection is a safe procedure and whether if has any beneficial effect over that of local bile duct excision alone, in terms of achieving curative resection and long-term survival. The records of 151 patients with hilar bile duct carcinoma surgically treated between June 1989 and December 1997 at the Asan Medical Center, Seoul, were retrospectively analyzed. Surgical resection was possible in 128 patients. The remaining 23 patients had surgical palliative drainage. Local bile duct excision alone was performed in 17 patients. Liver resection for tumor extending to secondary bile ducts or hepatic parenchyma was performed in 111 patients; portal vein resection was necessary in 29 of these 111 patients (26.1%) and pancreatoduodenectomy was combined in 18 patients (16.2%). Seven patients died during hospitalization after liver resection, an operative mortality of 6.3%. Margins of bile duct resection were free of tumor on histologic examination in 4 of the 17 local bile duct excisions, but in 86 of the 111 liver resections. The cumulative survival rate after local bile duct excision was 85.7% at 1 year, 42.9% at 2 years, 21.4% at 3 years, and 0% at 4 years. However, the survival rate after liver resection (excluding operative mortality) was 97.1% at 1 year, 72.8% at 2 years, 55.3% at 3 years, and 24.0% at 5 years. Survival and the percentage of patients with tumor-free resection margins after liver resection were superior to those after local bile duct excision. Resection of hilar bile duct carcinoma offers long-term survival only when surgery is aggressive and includes liver resection.

Adult-to-adult living donor liver transplantation at the Asan Medical Center, Korea

Between February 1997 and December 2001, 311 adult-to-adult living donor liver transplants (A-A LDLTs) were performed at the Asan Medical Center for patients above 20 years of age. Indications for A-A LDLT were: chronic hepatitis B (203), chronic hepatitis C (5), hepatocellular carcinoma (64), alcoholic cirrhosis (9), cryptogenic cirrhosis (4), secondary biliary cirrhosis (5), primary biliary cirrhosis (1), Wilson' s disease (2), autoimmune hepatitis (1), hepatic tuberculosis (1), cholangiocarcinoma (1), fulminant hepatic failure (14) and primary non-function of cadaveric liver graft (1). Of 311 A-A LDLTs, 36 were of medical high urgency, 20 were for acute and subacute hepatic failure, 15 were for hepato-renal syndrome and 1 was for primary non-function. Recipient age ranged from 27 to 64 years. Donor age ranged from 16 to 62 years. There was no donor mortality. Implanted liver grafts were categorized into seven types: 175 modified right lobe (MRL), 70 left lobe, 32 right lobe, 20 dual grafts, 10 left lobe plus caudate lobe, three extended right lobe and one posterior segment. In MRL, the tributaries of the middle hepatic vein were reconstructed by interpositioning a vein graft. Indication for dual graft implantation was the same as single graft A-A LDLT, and four of 20 were emergency cases. Of 20 dual grafts, 14 received two left lobes, four received a left lobe and a lateral segment, one received a right lobe and a left lobe and one received a lateral segment and a posterior segment. Graft volume ranged from 28% to 83% of the standard liver volume of the recipients. There were 33 (10.6%) in-hospital mortalities (< 4 months) among the 310 patients after 311 A-A LDLTs. Of the 36 patients receiving emergency transplants, 31 survived. These encouraging results justify the expansion of A-A LDLT in coping with increasing demands, even in urgent situations. We have aimed to introduce the establishment of the efficacy of A-A LDLT in various end-stage chronic and acute liver diseases, as well as new technical advances to overcome small graft-size syndrome by using dual-graft implantation and MRL, both of which were first developed in our department.

Avoiding a spanning cluster in percolation models

When dynamics in a system proceeds under suppressive external bias, the system can undergo an abrupt phase transition, as can happen when an epidemic spreads. Recently, an explosive percolation (EP) model was introduced to understand such phenomena. The order of the EP transition has not been clarified in a unified framework covering low-dimensional systems and the mean-field limit. We introduce a stochastic model in which a rule for dynamics is designed to avoid the formation of a spanning cluster through competitive selection in Euclidean space. We use heuristic arguments to show that in the thermodynamic limit and depending on a control parameter, the EP transition can be either continuous or discontinuous if d < d(c) and is always continuous if d ≥ d(c), where d(c) is the spatial dimension and d is the upper critical dimension.

ABO-Incompatible Adult Living Donor Liver Transplantation Under the Desensitization Protocol With Rituximab

ABO incompatibility is no longer considered a contraindication for adult living donor liver transplantation (ALDLT) due to various strategies to overcome the ABO blood group barrier. We report the largest single-center experience of ABO-incompatible (ABOi) ALDLT in 235 adult patients. The desensitization protocol included a single dose of rituximab and total plasma exchange. In addition, local graft infusion therapy, cyclophosphamide, or splenectomy was used for a certain time period, but these treatments were eventually discontinued due to adverse events. There were three cases (1.3%) of in-hospital mortality. The cumulative 3-year graft and patient survival rates were 89.2% and 92.3%, respectively, and were comparable to those of the ABO-compatible group (n = 1301). Despite promising survival outcomes, 17 patients (7.2%) experienced antibody-mediated rejection that manifested as diffuse intrahepatic biliary stricture; six cases required retransplantation, and three patients died. ABOi ALDLT is a feasible method for expanding a living liver donor pool, but the efficacy of the desensitization protocol in targeting B cell immunity should be optimized.

The transcriptional activity of cAMP response element-binding protein-binding protein is modulated by the latency associated nuclear antigen of Kaposi's sarcoma-associated herpesvirus

A multifunctional transcription co-activator, cAMP response element-binding protein-binding protein (CBP)interacts with a number of cellular factors and participates in cell growth, transformation, and development. It is also targeted by many viral proteins for their transcriptional activity or for the regulation of cellular processes. Here, we report that the C/H3 region of CBP is targeted by the latency associated nuclear antigen (LANA) of Kaposi's sarcoma-associated herpesvirus (KSHV). LANA interferes with the interaction between CBP and c-Fos, a representative C/H3 region binding, cellular transcription factor, in vivo and in vitro. In addition, we found that LANA inhibits the transcriptional activity and the in vitro histone acetyltransferase activity of CBP, suggesting that LANA modulates the global transcriptional activities of infected cells through the interaction with CBP. These results indicate that KSHV follows one of the conserved strategies, which other viruses utilize for influencing the cellular processes.

Disrupted yeast mitochondria can import precursor proteins directly through their inner membrane

Import of precursor proteins into the yeast mitochondrial matrix can occur directly across the inner membrane. First, disruption of the outer membrane restores protein import to mitochondria whose normal import sites have been blocked by an antibody against the outer membrane or by a chimeric, incompletely translocated precursor protein. Second, a potential- and ATP-dependent import of authentic or artificial precursor proteins is observed with purified inner membrane vesicles virtually free of outer membrane components. Third, import into purified inner membrane vesicles is insensitive to antibody against the outer membrane. Thus, while outer membrane components are clearly required in vivo, the inner membrane contains a complete protein translocation system that can operate by itself if the outer membrane barrier is removed.

Social functioning and quality of life comparisons between obsessive-compulsive and schizophrenic disorders

Treatment of obsessive-compulsive disorder has focused almost exclusively on symptom reduction; however, deficits in social functioning and quality of life of individuals with this disorder may contribute more to their "burden," suffering, and disability. To gauge the significance of social dysfunction and quality of life of persons with obsessive-compulsive disorder (OCD), we made comparisons with a group of persons with schizophrenia matched for age and gender. Thirty-one patients with OCD participating in a partial hospital treatment program were compared with 68 schizophrenic outpatients participating in a day rehabilitation program. The Independent Living Skills Survey (ILSS) and Lehman Quality of Life Scale (QOL) were administered before and after treatment for both cohorts. QOL scores were significantly lower for the OCD patients both before and after treatment, but improved significantly during treatment. OCD and schizophrenic patients had similar scores on almost every domain of the ILSS at pretreatment. The OCD patients improved significantly on many of the domains of social and independent living skills as a result of treatment and acquired significantly greater skills by post-treatment than did their counterparts with schizophrenia; however, the performance of social and independent living skills by OCD patients remained less than satisfactory even in domains where they improved. In the areas of job and leisure skills, there were significant group-by-time interactions. We concluded that patients with severe OCD and patients with schizophrenia are equally socially impaired. However, OCD patients experience greater significant functional improvement with multimodal treatment.

Transcription of tufA and other chloroplast-encoded genes is controlled by a circadian clock in Chlamydomonas

Levels of mRNA for the chloroplast-encoded elongation factor Tu (tufA) showed a dramatic daily oscillation in the green alga Chlamydomonas reinhardtii, peaking once each day in the early light period. The oscillation of tufA mRNA levels continued in cells shifted to continuous light or continuous dark for at least 2-3 days. Run-off transcription analyses showed that the rate of tufA transcription also peaked early in the light period and, moreover, that this transcriptional oscillation continued in cells shifted to continuous conditions. The half-life of tufA mRNA was estimated at different times and found to vary considerably during a light-dark cycle but not in cells shifted to continuous light. Light-dark patterns of transcription of several other chloroplast-encoded genes were examined and also found to persist in cells shifted to continuous light or dark. These results indicate that a circadian clock controls the transcription of tufA and other chloroplast-encoded genes.

The role of biomaterials in stem cell differentiation: applications in the musculoskeletal system

The capabilities of stem cells continue to be revealed, leading to excitement regarding potential new therapies. Regenerative medicine is an area in which stem cells hold great promise for overcoming the challenge of limited cell sources for tissue repair. Biomaterials play an important role in directing tissue growth and may provide another tool to manipulate and control stem cell behavior. Biomaterials are made from natural or synthetic polymers and can be processed into three-dimensional scaffolds designed to promote cell proliferation and/or differentiation that ultimately produces new tissue. Stem cells will have a significant impact on the fields of regenerative medicine and tissue engineering as a powerful cell source that will work, in conjunction with biomaterials, to treat tissue and organ loss. Herein, we survey our latest research on applying embryonic stem (ES) cells to hydrogel biomaterials for engineering musculoskeletal tissues, emphasizing the unique biomaterial requirements of ES cells for differentiation and tissue development.