Increase in the Expression of Glucose Transporter 2 (GLUT2) on the Peripheral Blood Insulin-Producing Cells (PB-IPC) in Type 1 Diabetic Patients after Receiving Stem Cell Educator Therapy.

Multicenter international clinical trials demonstrated the clinical safety and efficacy by using stem cell educator therapy to treat type 1 diabetes (T1D) and other autoimmune diseases. Previous studies characterized the peripheral blood insulin-producing cells (PB-IPC) from healthy donors with high potential to give rise to insulin-producing cells. PB-IPC displayed the molecular marker glucose transporter 2 (GLUT2), contributing to the glucose transport and sensing. To improve the clinical efficacy of stem cell educator therapy in the restoration of islet ß-cell function, we explored the GLUT2 expression on PB-IPC in recent onset and longstanding T1D patients. In the Food and Drug Administration (FDA)-approved phase 2 clinical studies, patients received one treatment with the stem cell educator therapy. Peripheral blood mononuclear cells (PBMC) were isolated for flow cytometry analysis of PB-IPC and other immune markers before and after the treatment with stem cell educator therapy. Flow cytometry revealed that both recent onset and longstanding T1D patients displayed very low levels of GLUT2 on PB-IPC. After the treatment with stem cell educator therapy, the percentages of GLUT2+CD45RO+ PB-IPC were markedly increased in these T1D subjects. Notably, we found that T1D patients shared common clinical features with patients with other autoimmune and inflammation-associated diseases, such as displaying low or no expression of GLUT2 on PB-IPC at baseline and exhibiting a high profile of the inflammatory cytokine interleukin (IL)-1ß. Flow cytometry demonstrated that their GLUT2 expressions on PB-IPC were also markedly upregulated, and the levels of IL-1ß-positive cells were significantly downregulated after the treatment with stem cell educator therapy. Stem cell educator therapy could upregulate the GLUT2 expression on PB-IPC and restore their function in T1D patients, leading to the improvement of clinical outcomes. The clinical data advances current understanding about the molecular mechanisms underlying the stem cell educator therapy, which can be expanded to treat patients with other autoimmune and inflammation-associated diseases.

Long-Term Decrease in Intraocular Pressure in Survivors of Ebola Virus Disease in the Partnership for Research on Vaccines and Infectious Diseases in Liberia (PREVAIL) III Study.

Objective: Survivors of Ebola virus disease (EVD) experience decreased intraocular pressure (IOP) relative to unaffected close contacts during the first year of convalescence. Whether this effect persists over time and its relationship to intraocular pathology are unclear. We sought to determine whether IOP remained lower in survivors of EVD over 4 years of follow-up and to identify associated risk factors. Design: Partnership for Research on Vaccines and Infectious Diseases in Liberia (PREVAIL) III is a 5-year, longitudinal cohort study of survivors of EVD and their close contacts and is a collaboration between the Liberian Ministry of Health and the United States National Institutes of Health. Participants: Participants who enrolled in PREVAIL III at John F. Kennedy Medical Center in Liberia, West Africa from June 2015 to March 2016 who underwent comprehensive ophthalmic evaluation annually for 5 consecutive visits. Methods: Intraocular pressure was measured at each visit by a handheld rebound tonometer using sterile tips. Comparisons are made between antibody-positive survivors and antibody-negative close contacts. Main Outcome Measures: Intraocular pressure, measured in mmHg, at each study visit. Results: Of 565 antibody-positive survivors and 644 antibody-negative close contacts enrolled in the study at baseline, the majority of participants returned annually, with 383 (67.8%) and 407 (63.2%) participants, respectively, presenting for the final study visit at a median of 60 months after symptom onset. A sustained, relative decrease in IOP was observed in survivors relative to close contacts, with mean difference of -0.72 mmHg (95% confidence interval [CI] -1.18 to -0.27) at the final study visit. This difference remained constant throughout the study period (P = 0.4 for interaction over time). Among survivors, physical examination findings of vitreous cell and OCT findings of vitreous opacities both demonstrated a significant association with decreased IOP at baseline (P < 0.05 for both). After adjusting for such factors, the difference throughout the follow-up (-0.93 mmHg, 95% CI, -1.23 to -0.63) remained significant. Conclusions: Survivors of EVD experienced a sustained decrease in IOP relative to close contacts over a 5-year period after EVD. The results highlight the importance of considering long-term sequelae of emerging infectious diseases within a population. Financial Disclosures: Proprietary or commercial disclosure may be found after the references.

Demographic Factors Associated with Presenting for Eye Evaluation in the Partnership for Research on Vaccines and Infectious Diseases in Liberia III Natural History Study of Ebola Virus Disease.

PURPOSE: Survivors of Ebola virus disease (EVD) are at risk for ocular complications after infection. We sought to identify demographic factors associated with the likelihood to present for eye examination among Ebola survivors enrolled in a longitudinal natural history study of EVD. METHODS: The Partnership for Research on Vaccines and Infectious Diseases in Liberia (PREVAIL) III Ebola natural history study is a 5-year study that seeks to identify long-term sequelae of EVD, including ocular sequelae. All survivors enrolled in the PREVAIL parent study from June 2015 to March 2016 were asked to return for comprehensive eye examination through June 2016. Logistic regression was conducted using self-reported survivor status, age, gender, and distance from the hospital as covariates. RESULTS: A total of 1448 subjects enrolled in the parent PREVAIL III longitudinal cohort during the defined window, of which 1375 (95.0%) followed up for baseline eye examination. Ebola survivors (635/661, 96.1%) and adult close contacts (727/767, 94.8%) demonstrated a comparable likelihood for presenting for eye examination (odds ratio [OR] 0.68, 95% confidence interval [CI] 0.36-1.28). In an adjusted model, age over 50 (OR 10.2, 95% CI 1.35-77.3) and living outside Montserrado County (OR 0.18, 95% CI 0.10-0.33) were associated with the likelihood of presenting for a baseline comprehensive eye examination. CONCLUSION: Most EVD survivors and their close contacts who enrolled during the study window presented for eye examinations. Older participants and those who lived closer to clinical facilities were most likely to present. Focused strategies accounting for these factors may assist with organizations planning survivor care in the setting of EVD.

Efficacy and Safety Outcomes of Cataract Surgery in Survivors of Ebola Virus Disease: 12-Month Results From the PREVAIL VII Study.

Purpose: In survivors of Ebola virus disease (EVD), intraocular viral persistence raises questions about the timing and safety of cataract surgery. To the best of our knowledge, this is the first controlled study evaluating Ebola virus persistence and cataract surgery safety and outcomes in EVD survivors. Methods: Seropositive EVD survivors and seronegative controls with vision worse than 20/40 from cataract and without active intraocular inflammation were enrolled. Aqueous humor from survivors was tested with reverse transcription-polymerase chain reaction for Ebola viral RNA. Participants underwent manual small-incision cataract surgery and 1 year of follow-up examinations. Results: Twenty-two eyes of 22 survivors and 12 eyes of eight controls underwent cataract surgery. All of the aqueous samples tested negative for Ebola viral RNA. Median visual acuity improved from 20/200 at baseline to 20/25 at 1 year in survivors and from count fingers to 20/50 in controls (overall, P < 0.001; between groups, P = 0.07). After a 1-month course of topical corticosteroids, 55% of survivors and 67% of controls demonstrated at least 1+ anterior chamber cell. Twelve months after surgery, optical coherence tomography revealed a median increase in macular central subfield thickness of 42 µm compared with baseline (overall, P = 0.029; between groups, P = 0.995). Conclusions: EVD survivors and controls demonstrated significant visual improvement from cataract surgery. The persistence of intraocular inflammation highlights the importance of follow-up. The absence of detectable intraocular Ebola viral RNA provides guidance regarding the safety of eye surgery in Ebola survivors. Translational Relevance: These findings demonstrate the safety and efficacy of cataract surgery in Ebola survivors and will inform ocular surgery guidelines in this population.

Characterization of Ebola Virus-Associated Eye Disease.

Importance: Survivors of Ebola virus disease (EVD) may experience ocular sequelae. Comparison with antibody-negative individuals from the local population is required to characterize the disease. Objective: To assess features of ophthalmic disease specific to EVD. Design, Setting, and Participants: This baseline cross-sectional analysis of survivors of EVD and their close contacts was conducted within PREVAIL III, a 5-year, longitudinal cohort study. Participants who enrolled at John F. Kennedy Medical Center in Liberia, West Africa from June 2015 to March 2016 were included in this analysis. Close contacts were defined as household members or sex partners of survivors of EVD. Data were analyzed from July 2016 to July 2020. Exposures: All participants, both survivors and close contacts, underwent testing of IgG antibody levels against Ebola virus surface glycoprotein. Main Outcomes and Measures: Ocular symptoms, anterior and posterior ophthalmologic examination findings, and optical coherence tomography images were compared between antibody-positive survivors and antibody-negative close contacts. Results: A total of 564 antibody-positive survivors (320 [56.7%] female; mean [SD] age, 30.3 [14.0] years) and 635 antibody-negative close contacts (347 [54.6%] female; mean [SD] age, 25.8 [15.5] years) were enrolled in this study. Survivors were more likely to demonstrate color vision deficit (28.9% vs 19.0%, odds ratio [OR], 1.6; 95% CI, 1.2-2.1) and lower intraocular pressure (12.4 vs 13.5 mm Hg; mean difference, -1.2 mm Hg; 95% CI, -1.6 to -0.8 mm Hg) compared with close contacts. Dilated fundus examination revealed a higher percentage of vitreous cells (7.8% vs 0.5%; OR, 16.6; 95% CI, 5.0-55.2) and macular scars (4.6% vs 1.6%; OR, 2.8; 95% CI, 1.4-5.5) in survivors than in close contacts. Uveitis was present in 26.4% of survivors and 12.1% of close contacts (OR, 2.4; 95% CI, 1.8-3.2). Among all participants with uveitis, survivors were more likely than close contacts to have intermediate uveitis (34.2% vs 6.5% of all cases; OR, 7.8; 95% CI, 3.1-19.7) and had thicker mean central subfield thickness on optical coherence tomography (222 vs 212 µm; mean difference, 14.4 µm; 95% CI, 1.9-26.9 µm). Conclusions and Relevance: In this cross-sectional study, survivors of EVD had a distinct spectrum of ocular and neuro-ophthalmologic findings compared with close contacts that potentially require medical and surgical treatment.

Oligomerization of the Vesicular Stomatitis Virus Phosphoprotein Is Dispensable for mRNA Synthesis but Facilitates RNA Replication.

Nonsegmented negative-strand (NNS) RNA viruses possess a ribonucleoprotein template in which the genomic RNA is sequestered within a homopolymer of nucleocapsid protein (N). The viral RNA-dependent RNA polymerase (RdRP) resides within an approximately 250-kDa large protein (L), along with unconventional mRNA capping enzymes: a GDP:polyribonucleotidyltransferase (PRNT) and a dual-specificity mRNA cap methylase (MT). To gain access to the N-RNA template and orchestrate the LRdRP, LPRNT, and LMT, an oligomeric phosphoprotein (P) is required. Vesicular stomatitis virus (VSV) P is dimeric with an oligomerization domain (OD) separating two largely disordered regions followed by a globular C-terminal domain that binds the template. P is also responsible for bringing new N protomers onto the nascent RNA during genome replication. We show VSV P lacking the OD (PΔOD) is monomeric but is indistinguishable from wild-type P in supporting mRNA transcription in vitro Recombinant virus VSV-PΔOD exhibits a pronounced kinetic delay in progeny virus production. Fluorescence recovery after photobleaching demonstrates that PΔOD diffuses 6-fold more rapidly than the wild type within viral replication compartments. A well-characterized defective interfering particle of VSV (DI-T) that is only competent for RNA replication requires significantly higher levels of N to drive RNA replication in the presence of PΔOD We conclude P oligomerization is not required for mRNA synthesis but enhances genome replication by facilitating RNA encapsidation.IMPORTANCE All NNS RNA viruses, including the human pathogens rabies, measles, respiratory syncytial virus, Nipah, and Ebola, possess an essential L-protein cofactor, required to access the N-RNA template and coordinate the various enzymatic activities of L. The polymerase cofactors share a similar modular organization of a soluble N-binding domain and a template-binding domain separated by a central oligomerization domain. Using a prototype of NNS RNA virus gene expression, vesicular stomatitis virus (VSV), we determined the importance of P oligomerization. We find that oligomerization of VSV P is not required for any step of viral mRNA synthesis but is required for efficient RNA replication. We present evidence that this likely occurs through the stage of loading soluble N onto the nascent RNA strand as it exits the polymerase during RNA replication. Interfering with the oligomerization of P may represent a general strategy to interfere with NNS RNA virus replication.

Detection of Cell Surface Ligands for Human Synovial γδ T Cells.

Lack of understanding of the nature and physiological regulation of γδ T cell ligands has considerably hampered full understanding of the function of these cells. We developed an unbiased approach to identify human γδ T cells ligands by the production of a soluble TCR-γδ (sTCR-γδ) tetramer from a synovial Vδ1 γδ T cell clone from a Lyme arthritis patient. The sTCR-γδ was used in flow cytometry to initially define the spectrum of ligand expression by both human tumor cell lines and certain human primary cells. Analysis of diverse tumor cell lines revealed high ligand expression on several of epithelial or fibroblast origin, whereas those of hematopoietic origin were largely devoid of ligand. This allowed a bioinformatics-based identification of candidate ligands using RNAseq data from each tumor line. We further observed that whereas fresh monocytes and T cells expressed low to negligible levels of TCR-γδ ligands, activation of these cells resulted in upregulation of surface ligand expression. Ligand upregulation on monocytes was partly dependent upon IL-1ß. The sTCR-γδ tetramer was then used to bind candidate ligands from lysates of activated monocytes and analyzed by mass spectrometry. Surface TCR-γδ ligand was eliminated by treatment with trypsin or removal of glycosaminoglycans, and also suppressed by inhibition of endoplasmic reticulum-Golgi transport. Of particular interest was that inhibition of glycolysis also blocked TCR-γδ ligand expression. These findings demonstrate the spectrum of ligand(s) expression for human synovial Vδ1 γδ T cells as well as the physiology that regulates their expression.

An In Vitro RNA Synthesis Assay for Rabies Virus Defines Ribonucleoprotein Interactions Critical for Polymerase Activity.

We report an in vitro RNA synthesis assay for the RNA-dependent RNA polymerase (RdRP) of rabies virus (RABV). We expressed RABV large polymerase protein (L) in insect cells from a recombinant baculovirus vector and the phosphoprotein cofactor (P) in Escherichia coli and purified the resulting proteins by affinity and size exclusion chromatography. Using chemically synthesized short RNA corresponding to the first 19 nucleotides (nt) of the rabies virus genome, we demonstrate that L alone initiates synthesis on naked RNA and that P serves to enhance the initiation and processivity of the RdRP. The L-P complex lacks full processivity, which we interpret to reflect the lack of the viral nucleocapsid protein (N) on the template. Using this assay, we define the requirements in P for stimulation of RdRP activity as residues 11 to 50 of P and formally demonstrate that ribavirin triphosphate (RTP) inhibits the RdRP. By comparing the properties of RABV RdRP with those of the related rhabdovirus, vesicular stomatitis virus (VSV), we demonstrate that both polymerases can copy the heterologous promoter sequence. The requirements for engagement of the N-RNA template of VSV by its polymerase are provided by the C-terminal domain (CTD) of P. A chimeric RABV P protein in which the oligomerization domain (OD) and the CTD were replaced by those of VSV P stimulated RABV RdRP activity on naked RNA but was insufficient to permit initiation on the VSV N-RNA template. This result implies that interactions between L and the template N are also required for initiation of RNA synthesis, extending our knowledge of ribonucleoprotein interactions that are critical for gene expression. IMPORTANCE: The current understanding of the structural and functional significance of the components of the rabies virus replication machinery is incomplete. Although structures are available for the nucleocapsid protein in complex with RNA, and also for portions of P, information on both the structure and function of the L protein is lacking. This study reports the expression and purification of the full-length L protein of RABV and the characterization of its RdRP activity in vitro The study provides a new assay that has utility for screening inhibitors and understanding their mechanisms of action, as well as defining new interactions that are required for RdRP activity.

3D non-woven polyvinylidene fluoride scaffolds: fibre cross section and texturizing patterns have impact on growth of mesenchymal stromal cells.

Several applications in tissue engineering require transplantation of cells embedded in appropriate biomaterial scaffolds. Such structures may consist of 3D non-woven fibrous materials whereas little is known about the impact of mesh size, pore architecture and fibre morphology on cellular behavior. In this study, we have developed polyvinylidene fluoride (PVDF) non-woven scaffolds with round, trilobal, or snowflake fibre cross section and different fibre crimp patterns (10, 16, or 28 needles per inch). Human mesenchymal stromal cells (MSCs) from adipose tissue were seeded in parallel on these scaffolds and their growth was compared. Initial cell adhesion during the seeding procedure was higher on non-wovens with round fibres than on those with snowflake or trilobal cross sections. All PVDF non-woven fabrics facilitated cell growth over a time course of 15 days. Interestingly, proliferation was significantly higher on non-wovens with round or trilobal fibres as compared to those with snowflake profile. Furthermore, proliferation increased in a wider, less dense network. Scanning electron microscopy (SEM) revealed that the MSCs aligned along the fibres and formed cellular layers spanning over the pores. 3D PVDF non-woven scaffolds support growth of MSCs, however fibre morphology and mesh size are relevant: proliferation is enhanced by round fibre cross sections and in rather wide-meshed scaffolds.

Kdo hydrolase is required for Francisella tularensis virulence and evasion of TLR2-mediated innate immunity.

UNLABELLED: The highly virulent Francisella tularensis subsp. tularensis has been classified as a category A bioterrorism agent. A live vaccine strain (LVS) has been developed but remains unlicensed in the United States because of an incomplete understanding of its attenuation. Lipopolysaccharide (LPS) modification is a common strategy employed by bacterial pathogens to avoid innate immunity. A novel modification enzyme has recently been identified in F. tularensis and Helicobacter pylori. This enzyme, a two-component Kdo (3-deoxy-d-manno-octulosonic acid) hydrolase, catalyzes the removal of a side chain Kdo sugar from LPS precursors. The biological significance of this modification has not yet been studied. To address the role of the two-component Kdo hydrolase KdhAB in F. tularensis pathogenesis, a ΔkdhAB deletion mutant was constructed from the LVS strain. In intranasal infection of mice, the ΔkdhAB mutant strain had a 50% lethal dose (LD(50)) 2 log(10) units higher than that of the parental LVS strain. The levels of the proinflammatory cytokines tumor necrosis factor alpha (TNF-α) and interleukin-1ß (IL-1ß) in bronchoalveolar lavage fluid were significantly higher (2-fold) in mice infected with the ΔkdhAB mutant than in mice infected with LVS. In vitro stimulation of bone marrow-derived macrophages with the ΔkdhAB mutant induced higher levels of TNF-α and IL-1ß in a TLR2-dependent manner. In addition, TLR2(-/-) mice were more susceptible than wild-type mice to ΔkdhAB bacterial infection. Finally, immunization of mice with ΔkdhAB bacteria elicited a high level of protection against the highly virulent F. tularensis subsp. tularensis strain Schu S4. These findings suggest an important role for the Francisella Kdo hydrolase system in virulence and offer a novel mutant as a candidate vaccine. IMPORTANCE: The first line of defense against a bacterial pathogen is innate immunity, which slows the progress of infection and allows time for adaptive immunity to develop. Some bacterial pathogens, such as Francisella tularensis, suppress the early innate immune response, killing the host before adaptive immunity can mature. To avoid an innate immune response, F. tularensis enzymatically modifies its lipopolysaccharide (LPS). A novel LPS modification-Kdo (3-deoxy-d-manno-octulosonic acid) saccharide removal--has recently been reported in F. tularensis. We found that the kdhAB mutant was significantly attenuated in mice. Additionally, the mutant strain induced an early innate immune response in mice both in vitro and in vivo. Immunization of mice with this mutant provided protection against the highly virulent F. tularensis strain Schu S4. Thus, our study has identified a novel LPS modification important for microbial virulence. A mutant lacking this modification may be used as a live attenuated vaccine against tularemia.

3-Deoxy-D-manno-octulosonic acid (Kdo) hydrolase identified in Francisella tularensis, Helicobacter pylori, and Legionella pneumophila.

3-Deoxy-D-manno-octulosonic acid (Kdo) is an eight-carbon sugar ubiquitous in Gram-negative bacterial lipopolysaccharides (LPS). Although its biosynthesis is well described, no protein has yet been identified as a Kdo hydrolase. However, Kdo hydrolase enzymatic activity has been detected in membranes of Helicobacter pylori and Francisella tularensis and may be responsible for the removal of side-chain Kdo from the LPS core saccharides. We now report the identification of genes encoding a Kdo hydrolase in F. tularensis Schu S4 and live vaccine strain strains, in H. pylori 26695 strain and in Legionella pneumophila Philadelphia 1 strain. We have renamed the genes kdhA for keto-deoxyoctulosonate hydrolase A. Deletion of kdhA abolished Kdo hydrolase activity in membranes of F. tularensis live vaccine strain. The F. tularensis kdhA mutant synthesized a core oligosaccharide containing a Kdo disaccharide with one of the Kdo residues being a terminal side chain. This side-chain Kdo monosaccharide was absent in the wild-type core oligosaccharide. Expression in Escherichia coli of recombinant KdhA from F. tularensis, H. pylori, and L. pneumophila resulted in a reduction of membrane-associated side-chain Kdo. The identification of this previously faceless enzyme will accelerate study of the biosynthetic basis and biologic impact for postbiosynthetic LPS structural modification.

Characterization of the O-antigen polymerase (Wzy) of Francisella tularensis.

The O-antigen polymerase of gram-negative bacteria has been difficult to characterize. Herein we report the biochemical and functional characterization of the protein product (Wzy) of the gene annotated as the putative O-antigen polymerase, which is located in the O-antigen biosynthetic locus of Francisella tularensis. In silico analysis (homology searching, hydropathy plotting, and codon usage assessment) strongly suggested that Wzy is an O-antigen polymerase whose function is to catalyze the addition of newly synthesized O-antigen repeating units to a glycolipid consisting of lipid A, inner core polysaccharide, and one repeating unit of the O-polysaccharide (O-PS). To characterize the function of the Wzy protein, a non-polar deletion mutant of wzy was generated by allelic replacement, and the banding pattern of O-PS was observed by immunoblot analysis of whole-cell lysates obtained by SDS-PAGE and stained with an O-PS-specific monoclonal antibody. These immunoblot analyses showed that O-PS of the wzy mutant expresses only one repeating unit of O-antigen. Further biochemical characterization of the subcellular fractions of the wzy mutant demonstrated that (as is characteristic of O-antigen polymerase mutants) the low molecular weight O-antigen accumulates in the periplasm of the mutant. Site-directed mutagenesis based on protein homology and topology, which was carried out to locate a catalytic residue of the protein, showed that modification of specific residues (Gly(176), Asp(177), Gly(323), and Tyr(324)) leads to a loss of O-PS polymerization. Topology models indicate that these amino acids most likely lie in close proximity on the bacterial surface.

Cellular and humoral immunity are synergistic in protection against types A and B Francisella tularensis.

Herein we report studies with a novel combination vaccine that, when administered to mice, conferred protection against highly virulent strains of Francisella tularensis by stimulating both arms of the immune system. Our earlier studies with Ft.LVS::wbtA, an O-polysaccharide (OPS)-negative mutant derived from the available live vaccine strain of F. tularensis (Ft.LVS), elucidated the role of antibodies to the OPS - a key virulence determinant - in protection against virulent type A organisms. However, when expressed on the organism, the OPS enhances virulence. In contrast, in purified form, the OPS is completely benign. We hypothesized that a novel combination vaccine containing both a component that induces humoral immunity and a component that induces cellular immunity to this intracellular microbe would have an enhanced protective capacity over either component alone and would be much safer than the LVS vaccine. Thus we developed a combination vaccine containing both OPS (supplied in an OPS-tetanus toxoid glycoconjugate) to induce a humoral antibody response and strain Ft.LVS::wbtA (which is markedly attenuated by its lack of OPS) to induce a cell-mediated protective response. This vaccine protected mice against otherwise-lethal intranasal and intradermal challenge with wild-type F. tularensis strains Schu S4 (type A) and FSC 108 (type B). These results represent a significant advance in our understanding of immunity to F. tularensis and provide important insight into the development of a safer vaccine effective against infections caused by clinical type A and B strains of F. tularensis.

Marine pelagic ecosystems: the west Antarctic Peninsula.

The marine ecosystem of the West Antarctic Peninsula (WAP) extends from the Bellingshausen Sea to the northern tip of the peninsula and from the mostly glaciated coast across the continental shelf to the shelf break in the west. The glacially sculpted coastline along the peninsula is highly convoluted and characterized by deep embayments that are often interconnected by channels that facilitate transport of heat and nutrients into the shelf domain. The ecosystem is divided into three subregions, the continental slope, shelf and coastal regions, each with unique ocean dynamics, water mass and biological distributions. The WAP shelf lies within the Antarctic Sea Ice Zone (SIZ) and like other SIZs, the WAP system is very productive, supporting large stocks of marine mammals, birds and the Antarctic krill, Euphausia superba. Ecosystem dynamics is dominated by the seasonal and interannual variation in sea ice extent and retreat. The Antarctic Peninsula is one among the most rapidly warming regions on Earth, having experienced a 2 degrees C increase in the annual mean temperature and a 6 degrees C rise in the mean winter temperature since 1950. Delivery of heat from the Antarctic Circumpolar Current has increased significantly in the past decade, sufficient to drive to a 0.6 degrees C warming of the upper 300 m of shelf water. In the past 50 years and continuing in the twenty-first century, the warm, moist maritime climate of the northern WAP has been migrating south, displacing the once dominant cold, dry continental Antarctic climate and causing multi-level responses in the marine ecosystem. Ecosystem responses to the regional warming include increased heat transport, decreased sea ice extent and duration, local declines in icedependent Adélie penguins, increase in ice-tolerant gentoo and chinstrap penguins, alterations in phytoplankton and zooplankton community composition and changes in krill recruitment, abundance and availability to predators. The climate/ecological gradients extending along the WAP and the presence of monitoring systems, field stations and long-term research programmes make the region an invaluable observatory of climate change and marine ecosystem response.

Vitrectomy for chronic macular holes.

PURPOSE: To address the efficacy of surgical intervention for chronic macular holes. METHODS: The cases of 22 patients (23 eyes) who underwent pars plana vitrectomy with or without internal limiting membrane (ILM) peeling and use of 10% to 16% C3F8 gas for macular holes of duration of >1 year (mean, 4.2 years; range, 1.2-15 years) were retrospectively reviewed. Preoperative visual acuity ranged from 20/60 to 5/200 (mean, 20/278). Thirteen eyes (56.5%) had stage 3 macular holes, and 10 eyes (43.5%) had stage 4 macular holes. The mean age of the patients was 70.2 years (range, 47-78 years), and 20 (87%) were female. RESULTS: Nineteen (83%) of 23 macular holes were closed at final follow-ups at >/=9 months (mean, 4.67 years; range, 0.9-10.8 years). With one operation that included ILM peeling, 13 (81%) of 16 eyes had holes that closed. Seven eyes on which initial surgery without ILM peeling failed underwent reoperation with ILM peeling, and all but one had closed holes. ILM peeling was significant for surgical success of one operation (Fisher exact test, P = 0.0005). Postoperative visual acuity ranged from 20/30 to 20/800 (mean, 20/166). Improved vision with halving of the visual angle occurred in 16 eyes (70%). Nine eyes (39%) achieved visual acuity of 20/70 or better, and two eyes (8.7%) achieved visual acuity of 20/40 or better. One eye (4%) had worse visual acuity, and three eyes (13%) remained unchanged. Cataract was a possible cause of decreased vision in six eyes (26%) at the end of follow-up. CONCLUSION: Chronic macular holes can be surgically closed with visual improvement in most patients. ILM peeling is an important surgical factor for closure of the macular hole with one operation.

Validity of the Depression-Arkansas (D-ARK) Scale: a tool for measuring major depressive disorder.

The results of 2 validation studies for an assessment tool designed specifically for quality improvement and outcomes assessment efforts in mental healthcare are presented in this paper. The studies evaluated a new tool to assess the patient outcomes for major depressive disorder following treatment in routine clinical settings called the Depression-Arkansas Scale (D-ARK). Study 1 included 54 patients recruited from 3 hospital-based clinics (2 mental health clinics and 1 primary care clinic). Study 2 includes 827 patients from 5 clinical settings including a university based outpatient clinic, a VA based mental health clinic, and a managed-care program. These 2 very different studies provide preliminary evidence that the D-ARK may be a useful tool for quality improvement efforts in the mental healthcare setting. Specifically, they indicate that the D-ARK has strong validity when compared to 2 different research assessments, the Structured Clinical Interview for DSM-III-R, Patient Edition (SCID-P) and the Inventory to Diagnose Depression (IDD), and compared to clinical assessments using both the clinical diagnosis and a clinician checklist.