Empowering people living with HIV (PLHIV): unveiling care gaps and identifying opportunities for improving care for PLHIV in Singapore and Hong Kong.

INTRODUCTION: This study explored the behaviours of people living with HIV in Singapore and Hong Kong in terms of achieving and maintaining their physical and psychological wellbeing in relation to HIV, to identify the challenges and support needed in HIV care. METHODS: This qualitative study involved 90-minute interviews among Singapore and Hong Kong people living with HIV aged ≥18 years to explore health-related quality of life perceptions and gaps in patient empowerment in HIV care during February-May 2022. The COM-B (C: Capability; O: Opportunity; M: Motivation; B: Behaviour) framework was used during data analysis to identify behaviour facilitators and barriers for people living with HIV to achieve and maintain their wellbeing. Detailed accounts of respondents' experience of living with and managing HIV, that is what worked well, unmet needs and perceived significance of wellbeing indicators, were analysed qualitatively via a combination of inductive content and deductive frameworks. RESULTS: A total of 30 and 28 respondents were recruited from Singapore (SG) and Hong Kong (HK), respectively. Most respondents were aged 20-49 years (SG: 83.3%; HK: 64.3%), males (SG: 96.7%; HK: 92.9%), men who have sex with men (SG: 93.3%; HK: 71.4%), had university or higher education (SG: 73.3%; HK: 50.0%) and were fully employed (SG: 73.3%; HK: 57.1%). In both Singapore and Hong Kong, physical health was considered a key focus of overall wellbeing, albeit attention to long-term health associated with cardiovascular and renal health was less salient. The impact of symptoms, side effects of treatment, mood and sleep were among the top wellbeing indicators of importance. Respondents felt that insufficient information was provided by physicians, citing consultation time and resource constraints impeding further expression of concerns to their physicians during consultation. Respondents prioritized functional wellness and delegated psychosocial health to supportive care professionals, patient groups, families and/or friends. CONCLUSIONS: There is a need in Singapore and Hong Kong to empower people living with HIV to establish better communications with their physicians and be more involved in their treatment journey and equally prioritize their psychosocial wellbeing.

Loss of C9orf72 perturbs the Ran-GTPase gradient and nucleocytoplasmic transport, generating compositionally diverse Importin ß-1 granules.

A hexanucleotide (GGGGCC)n repeat expansion in C9orf72 causes amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), eliciting toxic effects through generation of RNA foci, dipeptide repeat proteins, and/or loss of C9orf72 protein. Defects in nucleocytoplasmic transport (NCT) have been implicated as a pathogenic mechanism underlying repeat expansion toxicity. Here, we show that loss of C9orf72 disrupts the Ran-GTPase gradient and NCT in vitro and in vivo. NCT disruption in vivo is enhanced by the presence of compositionally different types of cytoplasmic Importin ß-1 granule that exhibit neuronal subtype-specific properties. We show that the abundance of Importin ß-1 granules is increased in the context of C9orf72 deficiency, disrupting interactions with nuclear pore complex proteins. These granules appear to associate with the nuclear envelope and are co-immunoreactive for G3BP1 and K63-ubiquitin. These findings link loss of C9orf72 protein to gain-of-function mechanisms and defects in NCT.

A C-Terminally Truncated TDP-43 Splice Isoform Exhibits Neuronal Specific Cytoplasmic Aggregation and Contributes to TDP-43 Pathology in ALS.

Neuronal cytoplasmic aggregation and ubiquitination of TDP-43 is the most common disease pathology linking Amyotrophic Lateral Sclerosis (ALS) and frontotemporal lobar degeneration (FTLD). TDP-43 pathology is characterized by the presence of low molecular weight TDP-43 species generated through proteolytic cleavage and/or abnormal RNA processing events. In addition to N-terminally truncated TDP-43 species, it has become evident that C-terminally truncated variants generated through alternative splicing in exon 6 also contribute to the pathophysiology of ALS/FTLD. Three such variants are listed in UCSD genome browser each sharing the same C-terminal unique sequence of 18 amino acids which has been shown to contain a putative nuclear export sequence. Here we have identified an additional C-terminally truncated variant of TDP-43 in human spinal cord tissue. This variant, called TDP43C-spl, is generated through use of non-canonical splice sites in exon 6, skipping 1,020 bp and encoding a 272 aa protein lacking the C-terminus with the first 256 aa identical to full-length TDP-43 and the same 18 amino acid C-terminal unique sequence. Ectopic expression studies in cells revealed that TDP43C-spl was localized to the nucleus in astrocytic and microglial cell lines but formed cytoplasmic ubiquitinated aggregates in neuronal cell lines. An antibody raised to the unique 18 amino acid sequence showed elevated levels of C-terminally truncated variants in ALS spinal cord tissues, and co-labeled TDP-43 pathology in disease affected spinal motor neurons. The retention of this 18 amino acid sequence among several C-terminally truncated TDP-43 variants suggests important functional relevance. Our studies of TDP43C-spl suggest this may be related to the selective vulnerability of neurons to TDP-43 pathology and cell-subtype differences in nuclear export.

Prion protein with a mutant N-terminal octarepeat region undergoes cobalamin-dependent assembly into high-molecular weight complexes.

The cellular prion protein (PrPC) has a C-terminal globular domain and a disordered N-terminal region encompassing five octarepeats (ORs). Encounters between Cu(II) ions and four OR sites produce interchangeable binding geometries; however, the significance of Cu(II) binding to ORs in different combinations is unclear. To understand the impact of specific binding geometries, OR variants were designed that interact with multiple or single Cu(II) ions in specific locked coordinations. Unexpectedly, we found that one mutant produced detergent-insoluble, protease-resistant species in cells in the absence of exposure to the infectious prion protein isoform, scrapie-associated prion protein (PrPSc). Formation of these assemblies, visible as puncta, was reversible and dependent upon medium formulation. Cobalamin (Cbl), a dietary cofactor containing a corrin ring that coordinates a Co3+ ion, was identified as a key medium component, and its effect was validated by reconstitution experiments. Although we failed to find evidence that Cbl interacts with Cu-binding OR regions, we instead noted interactions of Cbl with the PrPC C-terminal domain. We found that some interactions occurred at a binding site of planar tetrapyrrole compounds on the isolated globular domain, but others did not, and N-terminal sequences additionally had a marked effect on their presence and position. Our studies define a conditional effect of Cbl wherein a mutant OR region can act in cis to destabilize a globular domain with a wild type sequence. The unexpected intersection between the properties of PrPSc's disordered region, Cbl, and conformational remodeling events may have implications for understanding sporadic prion disease that does not involve exposure to PrPSc.

Preoperative dental screening prior to cardiac valve surgery and 90-day postoperative mortality.

BACKGROUND: Preoperative dental screening before cardiac valve surgery is widely accepted but its required scope remains unclear. This study evaluates two preoperative dental screening (PDS) approaches, a focused approach (FocA) and a comprehensive approach (CompA), to compare postsurgical 90-day mortality. METHODS: Retrospective cohort analysis was performed on all patients who underwent valve surgery at Brigham and Women's Hospital with FocA and Massachusetts General Hospital with CompA of PDS approach from January 2009 to December 2016. Patients with intravenous drug abuse and systemic infections were excluded. Univariate, multivariable, and subgroup analysis was performed. RESULTS: A total of 1835 patients were included in the study. With FocA 96% of patients (1097/1143) received dental clearance in a single encounter with 3.3% receiving radiographs and undergoing dental extractions. With CompA 35.5% of patients (245/692) received dental clearance in a single encounter, 94.2% received radiographs, and 21.8% underwent dental extractions. There was no significant difference in 90-day mortality when comparing both PDS approach (10% vs 8.4%, P = .257). This remained unchanged in a multivariable model after adjusting for risk factors (odds ratio:1.32 [95%CI:0.91-1.93] [P = .14]). Reoperation due to infection was less in FocA (0.5%) vs CompA (2.6) (P < .001) and postoperative septicemia was increased in the FocA (1.7%) cohort when compared to the CompA (0.7%) (P < .001) patients. CONCLUSIONS: There was no difference in post valve surgery 90-day mortality between patients who underwent a FocA vs CompA of PDS.

Synaptic localization of C9orf72 regulates post-synaptic glutamate receptor 1 levels.

A hexanucleotide repeat expansion in a noncoding region of C9orf72 is the most common genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Reduction of select or total C9orf72 transcript and protein levels is observed in postmortem C9-ALS/FTD tissue, and loss of C9orf72 orthologues in zebrafish and C. elegans results in motor deficits. However, how the reduction in C9orf72 in ALS and FTD might contribute to the disease process remains poorly understood. It has been shown that C9orf72 interacts and forms a complex with SMCR8 and WDR41, acting as a guanine exchange factor for Rab GTPases. Given the known synaptosomal compartmentalization of C9orf72-interacting Rab GTPases, we hypothesized that C9orf72 localization to synaptosomes would be required for the regulation of Rab GTPases and receptor trafficking. This study combined synaptosomal and post-synaptic density preparations together with a knockout-confirmed monoclonal antibody for C9orf72 to assess the localization and role of C9orf72 in the synaptosomes of mouse forebrains. Here, we found C9orf72 to be localized to both the pre- and post-synaptic compartment, as confirmed by both post-synaptic immunoprecipitation and immunofluorescence labelling. In C9orf72 knockout (C9-KO) mice, we demonstrated that pre-synaptic Rab3a, Rab5, and Rab11 protein levels remained stable compared with wild-type littermates (C9-WT). Strikingly, post-synaptic preparations from C9-KO mouse forebrains demonstrated a complete loss of Smcr8 protein levels, together with a significant downregulation of Rab39b and a concomitant upregulation of GluR1 compared with C9-WT mice. We confirmed the localization of Rab39b downregulation and GluR1 upregulation to the dorsal hippocampus of C9-KO mice by immunofluorescence. These results indicate that C9orf72 is essential for the regulation of post-synaptic receptor levels, and implicates loss of C9orf72 in contributing to synaptic dysfunction and related excitotoxicity in ALS and FTD.

The risk of bias in observational studies of exposures (ROBINS-E) tool: concerns arising from application to observational studies of exposures.

BACKGROUND: Systematic reviews, which assess the risk of bias in included studies, are increasingly used to develop environmental hazard assessments and public health guidelines. These research areas typically rely on evidence from human observational studies of exposures, yet there are currently no universally accepted standards for assessing risk of bias in such studies. The risk of bias in non-randomised studies of exposures (ROBINS-E) tool has been developed by building upon tools for risk of bias assessment of randomised trials, diagnostic test accuracy studies and observational studies of interventions. This paper reports our experience with the application of the ROBINS-E tool. METHODS: We applied ROBINS-E to 74 exposure studies (60 cohort studies, 14 case-control studies) in 3 areas: environmental risk, dietary exposure and drug harm. All investigators provided written feedback, and we documented verbal discussion of the tool. We inductively and iteratively classified the feedback into 7 themes based on commonalities and differences until all the feedback was accounted for in the themes. We present a description of each theme. RESULTS: We identified practical concerns with the premise that ROBINS-E is a structured comparison of the observational study being rated to the 'ideal' randomised controlled trial. ROBINS-E assesses 7 domains of bias, but relevant questions related to some critical sources of bias, such as exposure and funding source, are not assessed. ROBINS-E fails to discriminate between studies with a single risk of bias or multiple risks of bias. ROBINS-E is severely limited at determining whether confounders will bias study outcomes. The construct of co-exposures was difficult to distinguish from confounders. Applying ROBINS-E was time-consuming and confusing. CONCLUSIONS: Our experience suggests that the ROBINS-E tool does not meet the need for an international standard for evaluating human observational studies for questions of harm relevant to public and environmental health. We propose that a simpler tool, based on empirical evidence of bias, would provide accurate measures of risk of bias and is more likely to meet the needs of the environmental and public health community.

Effect of length of dental resident clinical rotations on patient behavior.

AIM: The purpose of this retrospective chart review study was to determine if the length of residents' comprehensive dental care rotations in a general practice residency affected late cancellations, broken appointments, completion of treatment, timeliness of recall visits, emergency visits, and the need for redo of restorations and prostheses. METHODS: Patients who presented for comprehensive care from 2010 to 2013, during which residents had 3- to 4-month dental clinic rotations, comprised Group 1, and patients who presented for comprehensive care from 2013 to 2016, during which residents had 11-month dental clinic rotations, comprised Group 2. Subjects were excluded if they only presented for emergency care, they had only one visit, or their care was delivered in both time periods. There were 105 patients in Group 1 and 55 patients in Group 2. RESULTS: The statistically significant results were that Group 1 patients had more late cancellations and broken appointments and failed to reach recall status more often than Group 2 patients, and that Group 1 patients had fewer emergency visits. CONCLUSION: Within the limitations of this retrospective study, the results suggest that short block rotations have an adverse effect on resident experience and outcomes of patient care in a hospital outpatient setting.

An Outcomes Study of 40 Years of Graduates of a General Practice Dental Residency.

Assessing program quality and outcomes is essential to improve postgraduate dental education. This study's aims were to document career direction and practice patterns of graduates of the Brigham and Women's Hospital (BWH) General Practice Residency (GPR), to compare BWH GPR outcomes to those of other American GPRs, and to identify characteristics of the BWH GPR program that trainees valued. This was a retrospective cohort study with a sample comprised of BWH GPR graduates between 1973 and 2013. Outcomes examined included pursuit of specialty training and positions on academic or hospital staff. Data sources were a survey of BWH GPR graduates and published national surveys. Of the 190 BWH graduates (95% of total) who were located and contacted, 133 (70% response rate) completed the survey. Compared to national survey data, BWH GPR graduates were significantly more likely to be specialists, full-time hospital staff, or full-time or part-time dental school faculty. Most BWH graduates (96.2%) ranked the program as outstanding or good. Faculty characteristics were considered by BWH graduates to be the most important factors in judging program quality. Since faculty characteristics were the most important factors in residents' judgment of program quality, GPR programs should recruit, maintain, and develop a quality faculty in order to attract students.

Octarepeat region flexibility impacts prion function, endoproteolysis and disease manifestation.

The cellular prion protein (PrP(C)) comprises a natively unstructured N-terminal domain, including a metal-binding octarepeat region (OR) and a linker, followed by a C-terminal domain that misfolds to form PrP(S) (c) in Creutzfeldt-Jakob disease. PrP(C) ß-endoproteolysis to the C2 fragment allows PrP(S) (c) formation, while α-endoproteolysis blocks production. To examine the OR, we used structure-directed design to make novel alleles, 'S1' and 'S3', locking this region in extended or compact conformations, respectively. S1 and S3 PrP resembled WT PrP in supporting peripheral nerve myelination. Prion-infected S1 and S3 transgenic mice both accumulated similar low levels of PrP(S) (c) and infectious prion particles, but differed in their clinical presentation. Unexpectedly, S3 PrP overproduced C2 fragment in the brain by a mechanism distinct from metal-catalysed hydrolysis reported previously. OR flexibility is concluded to impact diverse biological endpoints; it is a salient variable in infectious disease paradigms and modulates how the levels of PrP(S) (c) and infectivity can either uncouple or engage to drive the onset of clinical disease.

Prion infections and anti-PrP antibodies trigger converging neurotoxic pathways.

Prions induce lethal neurodegeneration and consist of PrPSc, an aggregated conformer of the cellular prion protein PrPC. Antibody-derived ligands to the globular domain of PrPC (collectively termed GDL) are also neurotoxic. Here we show that GDL and prion infections activate the same pathways. Firstly, both GDL and prion infection of cerebellar organotypic cultured slices (COCS) induced the production of reactive oxygen species (ROS). Accordingly, ROS scavenging, which counteracts GDL toxicity in vitro and in vivo, prolonged the lifespan of prion-infected mice and protected prion-infected COCS from neurodegeneration. Instead, neither glutamate receptor antagonists nor inhibitors of endoplasmic reticulum calcium channels abolished neurotoxicity in either model. Secondly, antibodies against the flexible tail (FT) of PrPC reduced neurotoxicity in both GDL-exposed and prion-infected COCS, suggesting that the FT executes toxicity in both paradigms. Thirdly, the PERK pathway of the unfolded protein response was activated in both models. Finally, 80% of transcriptionally downregulated genes overlapped between prion-infected and GDL-treated COCS. We conclude that GDL mimic the interaction of PrPSc with PrPC, thereby triggering the downstream events characteristic of prion infection.

Adherence to cervical cancer screening varies by human papillomavirus vaccination status in a high-risk population.

Cervical cancer screening has reduced the incidence of cervical cancer over the past 75 years. The primary aim of this study was to determine if women receiving Gardasil™ (HPV4 vaccine) participated in future cervical cancer screening at the same rate as that observed for unvaccinated women matched on birth year and health care campus. This is a retrospective cohort study of subjects selected from 27,786 females born from 1980 to 1992 who received health care in the Truman Medical Center safety net health system in Kansas City Missouri, USA. 1154 women 14-26 years old who received at least one dose of HPV4 vaccine between 2006 and 2009 were chosen at random from the vaccine records. 1154 randomly chosen unvaccinated women were age and health campus matched to the vaccinated women and all were followed until July 1, 2013. Women who were screened after 21 years and received three vaccine doses before 21 years, had the lowest screening rate of 24%. Their only predictive factor for screening, compared to the unvaccinated, was being closer to 21 years than 14 years at vaccination (aOR = 1.71 95% CI: 1.45, 2.00). Women vaccinated with three doses and screened at or after 21 years had the highest screening rate of 84% predicting a six-fold increase in screening participation over no vaccine received (aOR = 5.94 95% CI: 3.77, 9.35). Our results suggest that women who receive HPV4 vaccination closer to 21 years, not 14, are more likely to participate in cervical cancer screening in an underserved US population.

Prion disease tempo determined by host-dependent substrate reduction.

The symptoms of prion infection can take years or decades to manifest following the initial exposure. Molecular markers of prion disease include accumulation of the misfolded prion protein (PrPSc), which is derived from its cellular precursor (PrPC), as well as downregulation of the PrP-like Shadoo (Sho) glycoprotein. Given the overlapping cellular environments for PrPC and Sho, we inferred that PrPC levels might also be altered as part of a host response during prion infection. Using rodent models, we found that, in addition to changes in PrPC glycosylation and proteolytic processing, net reductions in PrPC occur in a wide range of prion diseases, including sheep scrapie, human Creutzfeldt-Jakob disease, and cervid chronic wasting disease. The reduction in PrPC results in decreased prion replication, as measured by the protein misfolding cyclic amplification technique for generating PrPSc in vitro. While PrPC downregulation is not discernible in animals with unusually short incubation periods and high PrPC expression, slowly evolving prion infections exhibit downregulation of the PrPC substrate required for new PrPSc synthesis and as a receptor for pathogenic signaling. Our data reveal PrPC downregulation as a previously unappreciated element of disease pathogenesis that defines the extensive, presymptomatic period for many prion strains.

RGG repeats of PrP-like Shadoo protein bind nucleic acids.

Shadoo (Sho) is a central nervous system glycoprotein with characteristics similar to those of the cellular prion protein PrP(C), each containing a highly conserved hydrophobic domain (HD) and an N-terminal repeat region. Whereas PrP(C) includes histidine-containing octarepeats, the Sho region N-terminal to the HD includes tandem positively charged "RGG boxes", predicted to bind RNA. Here, we demonstrate that Sho binds DNA and RNA in vitro via this arginine-rich region.

Down-regulation of Shadoo in prion infections traces a pre-clinical event inversely related to PrP(Sc) accumulation.

During prion infections of the central nervous system (CNS) the cellular prion protein, PrP(C), is templated to a conformationally distinct form, PrP(Sc). Recent studies have demonstrated that the Sprn gene encodes a GPI-linked glycoprotein Shadoo (Sho), which localizes to a similar membrane environment as PrP(C) and is reduced in the brains of rodents with terminal prion disease. Here, analyses of prion-infected mice revealed that down-regulation of Sho protein was not related to Sprn mRNA abundance at any stage in prion infection. Down-regulation was robust upon propagation of a variety of prion strains in Prnp(a) and Prnp(b) mice, with the exception of the mouse-adapted BSE strain 301 V. In addition, Sho encoded by a TgSprn transgene was down-regulated to the same extent as endogenous Sho. Reduced Sho levels were not seen in a tauopathy, in chemically induced spongiform degeneration or in transgenic mice expressing the extracellular ADan amyloid peptide of familial Danish dementia. Insofar as prion-infected Prnp hemizygous mice exhibited accumulation of PrP(Sc) and down-regulation of Sho hundreds of days prior to onset of neurologic symptoms, Sho depletion can be excluded as an important trigger for clinical disease or as a simple consequence of neuronal damage. These studies instead define a disease-specific effect, and we hypothesize that membrane-associated Sho comprises a bystander substrate for processes degrading PrP(Sc). Thus, while protease-resistant PrP detected by in vitro digestion allows post mortem diagnosis, decreased levels of endogenous Sho may trace an early response to PrP(Sc) accumulation that operates in the CNS in vivo. This cellular response may offer new insights into the homeostatic mechanisms involved in detection and clearance of the misfolded proteins that drive prion disease pathogenesis.

Establishment and characterization of Prnp knockdown neuroblastoma cells using dual microRNA-mediated RNA interference.

Prion diseases are fatal transmissible neurodegenerative disorders. In the pathogenesis of the disease, the cellular prion protein (PrPC) is required for replication of abnormal prion (PrPSc), which results in accumulation of PrPSc. Although there have been extensive studies using Prnp knockout systems, the normal function of PrPC remains ambiguous. Compared with conventional germline knockout technologies and transient naked siRNA-dependent knockdown systems, newly constructed durable chained-miRNA could provide a cell culture model that is closer to the disease status and easier to achieve with no detrimental sequelae. The selective silencing of a target gene by RNA interference (RNAi) is a powerful approach to investigate the unknown function of genes in vitro and in vivo. To reduce PrPC expression, a novel dual targeting-microRNA (miRdual) was constructed. The miRdual, which targets N- and C- termini of Prnp simultaneously, more effectively suppressed PrPC expression compared with conventional single site targeting. Furthermore, to investigate the cellular change following PrPC depletion, gene expression analysis of PrPC interacting and/or associating genes and several assays including proliferation, viability and apoptosis were performed. The transcripts 670460F02Rik and Plk3, Ppp2r2b and Csnk2a1 increase in abundance and are reported to be involved in cell proliferation and mitochondrial-mediated apoptosis. Dual-targeting RNAi with miRdual against Prnp will be useful for analyzing the physiological function of PrPC in neuronal cell lines and may provide a potential therapeutic intervention for prion diseases in the future.

Diagnosis of depression in former injection drug users with chronic hepatitis C.

GOALS: This study seeks to define the performance characteristics of 2 common depression screening tests and how psychiatric diagnoses affect adherence to treatment. BACKGROUND: Hepatitis C virus is common in former injection drug users (IDU). Many former IDUs have depression, which may complicate treatment, and are often denied therapy. STUDY: Ninety patients with chronic hepatitis C virus and reported IDU were recruited from a Hepatology Clinic in Seattle. Subjects completed the Beck Depression Inventory (BDI) and Patient Health Questionnaire-9 (PHQ-9) before antiviral therapy. A psychiatrist administered the Mini International Neuropsychiatric Interview as the "gold standard." Adherence was measured by self-report of missed doses. RESULTS: The BDI and PHQ-9 were highly correlated (r=0.75). Using a BDI score of ≥20 and a PHQ-9 score of ≥10, 39% and 52%, respectively, were misclassified as being depressed, as compared with the Mini International Neuropsychiatric Interview. Maximal sensitivity (85.7%) and specificity (82.6%) was achieved using a BDI score cutoff of 31, with an area under the curve of 0.82. For the PHQ-9, a cutoff of 14 yielded the best sensitivity (85.7%) and specificity (73.9%) with an area under the curve of 0.84. Adherence to at least 80% of medications was achieved by the majority. CONCLUSIONS: Subjects reported good adherence and outcomes despite a high level of psychiatric comorbidity. The BDI and PHQ-9 were highly correlated but both tended to overdiagnose depression. A high score on BDI or PHQ-9 should not be the sole basis for withholding treatment. These patients should be evaluated by a psychiatrist to make an informed decision.

Interactome analyses identify ties of PrP and its mammalian paralogs to oligomannosidic N-glycans and endoplasmic reticulum-derived chaperones.

The physiological environment which hosts the conformational conversion of the cellular prion protein (PrP(C)) to disease-associated isoforms has remained enigmatic. A quantitative investigation of the PrP(C) interactome was conducted in a cell culture model permissive to prion replication. To facilitate recognition of relevant interactors, the study was extended to Doppel (Prnd) and Shadoo (Sprn), two mammalian PrP(C) paralogs. Interestingly, this work not only established a similar physiological environment for the three prion protein family members in neuroblastoma cells, but also suggested direct interactions amongst them. Furthermore, multiple interactions between PrP(C) and the neural cell adhesion molecule, the laminin receptor precursor, Na/K ATPases and protein disulfide isomerases (PDI) were confirmed, thereby reconciling previously separate findings. Subsequent validation experiments established that interactions of PrP(C) with PDIs may extend beyond the endoplasmic reticulum and may play a hitherto unrecognized role in the accumulation of PrP(Sc). A simple hypothesis is presented which accounts for the majority of interactions observed in uninfected cells and suggests that PrP(C) organizes its molecular environment on account of its ability to bind to adhesion molecules harboring immunoglobulin-like domains, which in turn recognize oligomannose-bearing membrane proteins.

Factors predictive of significant hepatic fibrosis in adults with chronic hepatitis B and normal serum ALT.

GOAL: This study examines the prevalence and correlates of significant liver fibrosis among patients with immunotolerant hepatitis B. BACKGROUND: Adults with chronic hepatitis B infection acquired early in life often have normal serum alanine aminotransferase (ALT) activity and high serum hepatitis B virus deoxyribonucleic acid loads (HBV DNA), known as "immunotolerant" hepatitis B. STUDY: We conducted a cross-sectional study of 28 hepatitis B patients with serum HBV DNA titer >10 copies/mL, positive hepatitis B envelope antigen, and persistently normal serum ALT in a tertiary care setting. Liver biopsies were reviewed by a single pathologist who was blinded to other data. The prevalence of significant hepatic fibrosis was determined using the hospital-defined upper limit of normal for ALT and 2 more stringent criteria proposed by recent studies. Statistical analyses were conducted to identify factors associated with hepatic fibrosis. RESULTS: The prevalence of stage 2 fibrosis using the hospital laboratory, more stringent, and most stringent definitions of normal serum ALT, was 32%, 32%, and 13%, respectively, corresponding to negative predictive values of 68%, 68%, and 88%, respectively. Age greater than 30 years (P=0.035), grade 2 liver inflammation (P=0.005), and lower serum HBV DNA level (mean 7.45 vs. 8.42 log10 copies/mL, P<0.001) were independently associated with stage 2 fibrosis on liver biopsy. CONCLUSIONS: These results highlight the need to use stringent definitions of normal serum ALT when making clinical decisions for patients with chronic hepatitis B. Older age and lower serum HBV DNA level predict significant hepatic fibrosis on biopsy. Our findings may guide decisions regarding liver biopsy among patients with immunotolerant hepatitis B.

Canonical WNT/beta-catenin signaling is required for ureteric branching.

WNT/beta-catenin signaling has an established role in nephron formation during kidney development. Yet, the role of beta-catenin during ureteric morphogenesis in vivo is undefined. We generated a murine genetic model of beta-catenin deficiency targeted to the ureteric bud cell lineage. Newborn mutant mice demonstrated bilateral renal aplasia or renal dysplasia. Analysis of the embryologic events leading to this phenotype revealed that abnormal ureteric branching at E12.5 precedes histologic abnormalities at E13.5. Microarray analysis of E12.5 kidney tissue identified decreased Emx2 and Lim1 expression among a small subset of renal patterning genes disrupted at the stage of abnormal branching. These alterations are followed by decreased expression of genes downstream of Emx2, including Lim1, Pax2, and the ureteric tip markers, c-ret and Wnt 11. Together, these data demonstrate that beta-catenin performs essential functions during renal branching morphogenesis via control of a hierarchy of genes that control ureteric branching.