To investigate deep and comprehensive analysis of gut microbial communities and biological parameters after prebiotic administration in obese and diabetic mice.
RESEARCH DESIGN AND METHODS
Genetic (ob/ob) or diet-induced obese and diabetic mice were chronically fed with prebiotic-enriched diet or with a control diet. Extensive gut microbiota analyses, including quantitative PCR, pyrosequencing of the 16S rRNA, and phylogenetic microarrays, were performed in ob/ob mice. The impact of gut microbiota modulation on leptin sensitivity was investigated in diet-induced leptin-resistant mice. Metabolic parameters, gene expression, glucose homeostasis, and enteroendocrine-related L-cell function were documented in both models.
In ob/ob mice, prebiotic feeding decreased Firmicutes and increased Bacteroidetes phyla, but also changed 102 distinct taxa, 16 of which displayed a >10-fold change in abundance. In addition, prebiotics improved glucose tolerance, increased L-cell number and associated parameters (intestinal proglucagon mRNA expression and plasma glucagon-like peptide-1 levels), and reduced fat-mass development, oxidative stress, and low-grade inflammation. In high fat–fed mice, prebiotic treatment improved leptin sensitivity as well as metabolic parameters.
We conclude that specific gut microbiota modulation improves glucose homeostasis, leptin sensitivity, and target enteroendocrine cell activity in obese and diabetic mice. By profiling the gut microbiota, we identified a catalog of putative bacterial targets that may affect host metabolism in obesity and diabetes.
Hepatitis E virus; homeless persons; HEV transmission; autochthonous hepatitis; injection drug use; France; viruses; letter
Growing evidence supports the role of gut microbiota in the development of obesity, type 2 diabetes, and low-grade inflammation. The endocrine activity of adipose tissue has been found to contribute to the regulation of glucose homeostasis and low-grade inflammation. Among the key hormones produced by this tissue, apelin has been shown to regulate glucose homeostasis. Recently, it has been proposed that gut microbiota participate in adipose tissue metabolism via the endocannabinoid system (eCB) and gut microbiota-derived compounds, namely lipopolysaccharide (LPS). We have investigated gut microbiota composition in obese and diabetic leptin-resistant mice (db/db) by combining pyrosequencing and phylogenetic microarray analysis of 16S ribosomal RNA gene sequences. We observed a significant higher abundance of Firmicutes, Proteobacteria, and Fibrobacteres phyla in db/db mice compared to lean mice. The abundance of 10 genera was significantly affected by the genotype. We identified the roles of the eCB and LPS in the regulation of apelinergic system tone (apelin and APJ mRNA expression) in genetic obese and diabetic mice. By using in vivo and in vitro models, we have demonstrated that both the eCB and low-grade inflammation differentially regulate apelin and APJ mRNA expression in adipose tissue. Finally, deep-gut microbiota profiling revealed that the gut microbial community of type 2 diabetic mice is significantly different from that of their lean counterparts. This indicates specific relationships between the gut microbiota and the regulation of the apelinergic system. However, the exact roles of specific bacteria in shaping the phenotype of db/db mice remain to be determined.
gut microbiota; type 2 diabetes; inflammation; LPS; endocannabinoid; apelin; APJ; metabolic endotoxemia
The HIV-1 RNA viral load is commonly used for the monitoring of disease progression and antiretroviral treatment of HIV-1-infected patients. Since the misestimating of values could lead to inappropriate therapeutical management, the comparative performances, especially the ability to span the genetic diversity of HIV-1, of available automated real-time assays need to be evaluated. We conducted a prospective study with 74 consenting patients enrolled between March 2007 and November 2008. A blood sample was obtained at the time of diagnosis of HIV seropositivity and blindly tested for HIV-1 RNA by at least 4 commercial tests: the Abbott m2000 RealTime HIV-1, bioMérieux NucliSens EasyQ HIV-1, version 1.2 (v1.2), and Cobas AmpliPrep/Cobas TaqMan (CAP/CTM) v1.0 and v2.0 assays. The means of difference were null between CAP/CTM v2.0 and Abbott for CRF02_AG subtypes but positive in favor of CAP/CTM v2.0 for genotype B and negative in favor of NucliSens for all genotypes. The standard deviation (SD) of difference ranged from 0.3 to 0.59, depending on the considered couples of assays. Reliabilities of these four tests, appreciated by the standard deviation of difference between the measurement and the estimated “true” viral load and by the coefficient of reliability, were significantly different (P < 10−4) among each other. Significant differences were also observed within each group of HIV-1 genotype. The global disparity was higher for CRF02_AG than for B subtypes. This study indicates a risk of viral load misestimating or discrepancies between techniques, depending on the HIV-1 subtype, and speaks in favor of using the same assay for the monitoring of HIV-1-infected patients.
We analyzed mortality among 201 patients with AIDS and tuberculosis in Haiti. Patients who received a diagnosis of tuberculosis during the first 3 months after the initiation of antiretroviral therapy were 3.25 times more likely to die than were other patients with AIDS and tuberculosis. Failure to recognize active tuberculosis at initiation of antiretroviral therapy leads to increased mortality.
We hypothesized that lymph nodes draining sites of cutaneous vaccination could be identified by sentinel node biopsy techniques, and that measuring T-cell response with lymphocytes obtained from these lymph nodes would provide a more sensitive measure of immunogenicity than would the same measurement made with peripheral blood lymphocytes (PBL).
ELISpot analysis was used to determine the magnitude of vaccine-specific T-cell response in the sentinel immunized nodes (SIN), random lymph nodes, and peripheral blood lymphocytes (PBL) obtained from patients enrolled in clinical trials of experimental melanoma vaccines.
The SIN biopsy was successful in 97%of cases and morbidity was very low. The T-cell response to vaccination was detected with greater sensitivity in the SIN(57%) than in PBL (39%), and evaluation of T-cell responses in the SIN and the PBL together yielded T-cell responses in 63% of patients. When the T-cell responses from a SIN and a random lymph node were compared in four patients, immune responses were detected to one of the vaccine peptides in three of these four patients. In all of those cases, responses were present in the SIN but absent from the random lymph node.
Measurements of T-cell responsiveness to cutaneous immunization are more frequently positive in the SIN than they are in the PBL, however evaluation of both the SIN and PBL permit a more sensitive measure of T-cell immunogenicity than use of either single source.
Understanding how hepatitis C virus (HCV) induces and circumvents the host's natural killer (NK) cell-mediated immunity is of critical importance in efforts to design effective therapeutics. We report here the decreased expression of the NKG2D activating receptor as a novel strategy adopted by HCV to evade NK-cell mediated responses. We show that chronic HCV infection is associated with expression of ligands for NKG2D, the MHC class I-related Chain (MIC) molecules, on hepatocytes. However, NKG2D expression is downmodulated on circulating NK cells, and consequently NK cell-mediated cytotoxic capacity and interferon-γ production are impaired. Using an endotoxin-free recombinant NS5A protein, we show that NS5A stimulation of monocytes through Toll-like Receptor 4 (TLR4) promotes p38- and PI3 kinase-dependent IL-10 production, while inhibiting IL-12 production. In turn, IL-10 triggers secretion of TGFβ which downmodulates NKG2D expression on NK cells, leading to their impaired effector functions. Moreover, culture supernatants of HCV JFH1 replicating Huh-7.5.1 cells reproduce the effect of recombinant NS5A on NKG2D downmodulation. Exogenous IL-15 can antagonize the TGFβ effect and restore normal NKG2D expression on NK cells. We conclude that NKG2D-dependent NK cell functions are modulated during chronic HCV infection, and demonstrate that this alteration can be prevented by exogenous IL-15, which could represent a meaningful adjuvant for therapeutic intervention.
Natural killer (NK) cells are part of the innate immune response against virus infection. Their activation is the net result of signals emanating from a panel of inhibitory and activating receptors, among which the NKG2D activating receptor plays a major role. NKG2D ligands, the MHC class I related Chain (MIC) molecules, are induced on HCV-infected hepatocytes. In this paper, we show that NKG2D expression is decreased on NK cells from chronically infected HCV patients. As a consequence, NK cell cytolytic and IFNγ-producing functions are impaired. We show that this phenomenon is mediated by TGFβ produced by monocytes upon stimulation by the non-structural HCV-NS5A protein. NS5A could bind to TLR4 on monocytes, thus inducing the production of IL-10 and TGFβ, while inhibiting the production of IL-12. We further showed that TLR4-dependent IL-10 production by monocytes upon NS5A stimulation was mediated through the p38 and PI3 kinase pathways. In addition, we demonstrated that IL-15 could inhibit the TGFβ-mediated effects on NKG2D expression and NK cell functions. Collectively, these results identify a new dampening signal used by HCV to subvert innate immune response, and may provide new insights into the design of new strategies to restore NK cell functions in chronic hepatitis C.
Background and aims
An algorithm based on a 2 log10 decline in hepatitis C virus (HCV) RNA at week (W) 12 has been proposed in US and European recommendations for the management of patients with chronic hepatitis C treated with pegylated‐interferon and ribavirin.
We examined rapid virological response (RVR; at W2 and W4 after the initiation of therapy) in HIV/HCV co‐infected patients. Using HCV RNA measurements (Versant HCV RNA 3.0, Cobas Amplicor HCV 2.0), RVR was studied in 323 patients from the ANRS HC02 RIBAVIC trial, comparing interferon α2b 3 MU ×3/week with pegylated interferon α2b 1.5 μg/kg/week, each combined with ribavirin 800 mg/day over 48 weeks.
The best positive and negative predictive values of sustained virological response (SVR) were obtained with an undetectable HCV RNA at W4 (97%) and with more than a 2 log10 decrease at W12 (99%), respectively. Prediction of non‐SVR was obtained in all patients by using HCV RNA cut‐off levels above 460 000 IU/ml at W4 and above 39 000 UI/ml at W12 irrespective of the HCV genotype and arm of treatment.
We propose a new algorithm based on RVR thresholds using HCV RNA that allows for excellent prediction of non‐SVR as early as W4.
HIV/HCV co‐infection; hepatitis C therapy; HCV viral load; rapid and early viral decline; prediction of response
A phase I/II trial was performed to evaluate the safety and immunogenicity of a novel melanoma vaccine comprising six melanoma-associated peptides defined as antigenic targets for melanoma-reactive helper T cells. Source proteins for these peptides include MAGE proteins, MART-1/MelanA, gp100, and tyrosinase.
Patients and Methods
Thirty-nine patients with stage IIIB to IV melanoma were vaccinated with this six-peptide mixture weekly at three dose levels, with a preceding phase I dose escalation and subsequent random assignment among the dose levels. Helper T-lymphocyte responses were assessed by in vitro proliferation assay and delayed-type hypersensitivity skin testing. Patients with measurable disease were evaluated for objective clinical response by Response Evaluation Criteria in Solid Tumors.
Vaccination with the helper peptide vaccine was well tolerated. Proliferation assays revealed induction of T-cell responses to the melanoma helper peptides in 81% of patients. Among 17 patients with measurable disease, objective clinical responses were observed in two patients (12%), with response durations of 1 and 3.9+ years. Durable stable disease was observed in two additional patients for periods of 1.8 and 4.6+ years.
Results of this study support the safety and immunogenicity of a vaccine comprised of six melanoma helper peptides. There is also early evidence of clinical activity.
OBJECTIVE—Synthetic ligands for peroxisome proliferator–activated receptor-γ (PPAR-γ) improve insulin sensitivity in obesity, but it is still unclear whether inflammatory signals modulate their metabolic actions. In this study, we tested whether targeted disruption of inducible nitric oxide (NO) synthase (iNOS), a key inflammatory mediator in obesity, modulates the metabolic effects of rosiglitazone in obese mice.
RESEARCH DESIGN AND METHODS—iNOS−/− and iNOS+/+ were subjected to a high-fat diet or standard diet for 18 weeks and were then treated with rosiglitazone for 2 weeks. Whole-body insulin sensitivity and glucose tolerance were determined and metabolic tissues harvested to assess activation of insulin and AMP-activated protein kinase (AMPK) signaling pathways and the levels of inflammatory mediators.
RESULTS—Rosiglitazone was found to similarly improve whole-body insulin sensitivity and insulin signaling to Akt/PKB in skeletal muscle of obese iNOS−/− and obese iNOS+/+ mice. However, rosiglitazone further improved glucose tolerance and liver insulin signaling only in obese mice lacking iNOS. This genotype-specific effect of rosiglitazone on glucose tolerance was linked to a markedly increased ability of the drug to raise plasma adiponectin levels. Accordingly, rosiglitazone increased AMPK activation in muscle and liver only in obese iNOS−/− mice. PPAR-γ transcriptional activity was increased in adipose tissue of iNOS−/− mice. Conversely, treatment of 3T3-L1 adipocytes with a NO donor blunted PPAR-γ activity.
CONCLUSIONS—Our results identify the iNOS/NO pathway as a critical modulator of PPAR-γ activation and circulating adiponectin levels and show that invalidation of this key inflammatory mediator improves the efficacy of PPAR-γ agonism in an animal model of obesity and insulin resistance.
Breast cancer is a complex and heterogeneous disease at the molecular level. Evolution is difficult to predict according to classical histoclinical prognostic factors. Different studies highlight the importance of large-scale molecular expression analyses to improve taxonomy of breast cancer and prognostic classification. Identification of new molecular markers that refine this taxonomy and improve patient management is a priority in the field of breast cancer research.
Nectins are cell adhesion molecules involved in the regulation of epithelial physiology. We present here Nectin-4/PVRL4 as a new histological and serological tumor associated marker for breast carcinoma.
Expression of Nectin-4 protein was measured on a panel of 78 primary cells and cell lines from different origins and 57 breast tumors by FACS analysis and immunohistochemistry (IHC), respectively. mRNA expression was measured by quantitative PCR.
Serum Nectin-4 was detected by ELISA and compared with CEA and CA15.3 markers, on panels of 45 sera from healthy donors, 53 sera from patients with non-metastatic breast carcinoma (MBC) at diagnosis, and 182 sera from patients with MBC. Distribution of histological/serological molecular markers and histoclinical parameters were compared using the standard Chi-2 test.
Nectin-4 was not detected in normal breast epithelium. By contrast, Nectin-4 was expressed in 61% of ductal breast carcinoma vs 6% in lobular type. Expression of Nectin-4 strongly correlated with the basal-like markers EGFR, P53, and P-cadherin, and negatively correlated with the luminal-like markers ER, PR and GATA3. All but one ER/PR-negative tumors expressed Nectin-4. The detection of Nectin-4 in serum improves the follow-up of patients with MBC: the association CEA/CA15.3/Nectin-4 allowed to monitor 74% of these patients compared to 67% with the association CEA/CA15.3. Serum Nectin-4 is a marker of disease progression, and levels correlate with the number of metastases (P = 0.038). Serum Nectin-4 is also a marker of therapeutic efficiency and correlates, in 90% of cases, with clinical evolution.
Nectin-4 is a new tumor-associated antigen for breast carcinoma. Nectin-4 is a new bio-marker whose use could help refine breast cancer taxonomy and improve patients' follow-up. Nectin-4 emerges as a potential target for breast cancer immunotherapy.
We report the isolation of chikungunya virus from a patient during an outbreak of a denguelike syndrome in Cameroon in 2006. The virus was phylogenetically grouped in the Democratic Republic of the Congo cluster, indicating a continuous circulation of a genetically similar chikungunya virus population during 6 years in Central Africa.
Chikungunya virus; alphavirus; Dengue viruses; arbovirus; Cameroon; dispatch
PAPRICA is a research program designed to estimate the impact on the health of patients with chronic respiratory insufficiency of a prevention strategy based on notification of ozone pollution. The first year of this study was conducted during the 2003 heat wave, and high temperatures were therefore considered as a confounding factor in the data analysis. The aim of the present study was to assess the relationship between ozone and temperature in order to propose a methodology to distinguish between the effects of ozone and temperature on the impact of a prevention strategy with regard to ozone pollution.
Multivariate analyses were used to identify associated climate and ozone pollution profiles. This descriptive method is of great value to highlight the complexity of interactions between these parameters.
Ozone concentration and temperature were strongly correlated, but the health impact of ozone pollution alone will be evaluated by focusing on situations characterized by ozone concentrations above 110 μg/m3/8h (air quality guidelines to protect human health defined by the French legislation) and temperatures lower than 26°C, below the discomfort threshold.
The precise relationship between ambient ozone concentration and temperature identified during the PAPRICA 2003 study period will be used in analysing the PAPRICA health data.
Human immunodeficiency virus (HIV) treatment self-efficacy is the confidence held by an individual in her or his ability to follow treatment recommendations, including specific HIV care such as initiating and adhering to antiretroviral therapy (ART). The purpose of this study was to explore the potential mediating role of treatment adherence self-efficacy in the relationships between Social Cognitive Theory constructs and self- reported ART adherence.
Cross-sectional and descriptive. The study was conducted between 2009 and 2011 and included 1,414 participants who lived in the United States or Puerto Rico and were taking antiretroviral medications.
Social cognitive constructs were tested specifically: behaviors (three adherence measures each consisting of one item about adherence at 3-day and 30-day along with the adherence rating scale), cognitive or personal factors (the Center for Epidemiology Studies Depression Scale to assess for depressive symptoms, the 12-Item Short Form Health Survey (SF-12) to assess physical functioning, one item about physical condition, one item about comorbidity), environmental influences (the Social Capital Scale, one item about social support), and treatment self-efficacy (HIV Adherence Self-Efficacy Scale). Analysis included descriptive statistics and regression.
The average participant was 47 years old, male, and a racial or ethnic minority, had an education of high school or less, had barely adequate or totally inadequate income, did not work, had health insurance, and was living with HIV/acquired immunodeficiency syndrome for 15 years. The model provided support for adherence self-efficacy as a robust predictor of ART adherence behavior, serving a partial mediating role between environmental influences and cognitive or personal factors.
Although other factors such as depressive symptoms and lack of social capital impact adherence to ART, nurses can focus on increasing treatment self-efficacy through diverse interactional strategies using principles of adult learning and strategies to improve health literacy.
Adherence to ART reduces the viral load thereby decreasing morbidity and mortality and risk of transmission to uninfected persons. Nurses need to use a variety of strategies to increase treatment self-efficacy.
HIV/AIDS; social cognitive theory; self-efficacy; adherence
Staphylococcus aureus can colonize and infect both humans and animals, but isolates from both hosts tend to belong to different lineages. Our recent finding of bovine-adapted S. aureus showing close genetic relationship to the human S. aureus clonal complex 8 (CC8) allowed us to examine the genetic basis of host adaptation in this particular CC. Using total chromosome microarrays, we compared the genetic makeup of 14 CC8 isolates obtained from cows suffering subclinical mastitis, with nine CC8 isolates from colonized or infected human patients, and nine S. aureus isolates belonging to typical bovine CCs. CC8 isolates were found to segregate in a unique group, different from the typical bovine CCs. Within this CC8 group, human and bovine isolates further segregated into three subgroups, among which two contained a mix of human and bovine isolates, and one contained only bovine isolates. This distribution into specific clusters and subclusters reflected major differences in the S. aureus content of mobile genetic elements (MGEs). Indeed, while the mixed human-bovine clusters carried commonly human-associated β-hemolysin converting prophages, the bovine-only isolates were devoid of such prophages but harbored an additional new non-mec staphylococcal cassette chromosome (SCC) unique to bovine CC8 isolates. This composite cassette carried a gene coding for a new LPXTG-surface protein sharing homologies with a protein found in the environmental bacterium Geobacillus thermoglucosidans. Thus, in contrast to human CC8 isolates, the bovine-only CC8 group was associated with the combined loss of β-hemolysin converting prophages and gain of a new SCC probably acquired in the animal environment. Remaining questions are whether the new LPXTG-protein plays a role in bovine colonization or infection, and whether the new SCC could further acquire antibiotic-resistance genes and carry them back to human.
New approaches to enhance access in primary care necessitate change in the model for residency education.
To describe instrument design, development and testing, and data collection strategies for residency programs, continuity clinics, residents, and program graduates participating in the Preparing the Personal Physician for Practice (P4) project.
We developed and pilot-tested surveys to assess demographic characteristics of residents, clinical and operational features of the continuity clinics and educational programs, and attitudes about and implementation status of Patient Centered Medical Home (PCMH) characteristics. Surveys were administered annually to P4 residency programs since the project started in 2007. Descriptive statistics were used to profile data from the P4 baseline year.
Most P4 residents were non-Hispanic white women (60.7%), married or partnered, attended medical school in the United States and were the first physicians in their families to attend medical school. Nearly 85% of residency continuity clinics were family health centers, and about 8% were federally qualified health centers. The most likely PCMH features in continuity clinics were having an electronic health record and having fully secure remote access available; both of which were found in more than 50% of continuity clinics. Approximately one-half of continuity clinics used the electronic health record for safety projects, and nearly 60% used it for quality-improvement projects.
We created a collaborative evaluation model in all 14 P4 residencies. Successful implementation of new surveys revealed important baseline features of residencies and residents that are pertinent to studying the effects of new training models for the PCMH.
Enterobacterial strains producing clavulanic-acid-inhibited extended-spectrum β-lactamases (ESBLs) are increasingly reported worldwide. Conventional detection of ESBL production remains time-consuming (24 to 48 h). Therefore, the ESBL NDP (Nordmann/Dortet/Poirel) test was developed for a rapid identification of ESBLs in Enterobacteriaceae. This biochemical test was based on the in vitro detection of a cephalosporin (cefotaxime) hydrolysis that is inhibited by tazobactam addition. The ESBL activity was evidenced by a color change (red to yellow) of a pH indicator (red phenol) due to carboxyl-acid formation resulting from cefotaxime hydrolysis that was reversed by addition of tazobactam (positive test). The ESBL NDP test was applied to cultured strains (215 ESBL producers and 40 ESBL nonproducers). Its sensitivity and specificity were 92.6% and 100%, respectively. Its sensitivity (100%) was excellent for detection of CTX-M producers. A few ESBL producers (n = 16) that remained susceptible to cefotaxime were not detected. The test was also evaluated on spiked blood cultures and showed excellent sensitivity and specificity (100% for both). The test was rapid (less than 1 h) and cost-effective. It can be implemented in any health care facility and is well adapted for infection control purposes in particular.
Vancomycin-resistant Staphylococcus aureus VRSA-10 was isolated in 2009, whereas VRSA-11A and VRSA-11B were isolated from the same patient in 2010. Growth curves and determination of the nature of the peptidoglycan precursors and of the VanX d,d-dipeptidase activity in the absence and in the presence of vancomycin indicated that vancomycin resistance was inducible in VRSA-10, that VRSA-11A was partially dependent on glycopeptide for growth, and that VRSA-11B was constitutively resistant. Both VRSA-11A and -11B harbored an insertion sequence, ISEf1, at the same locus in the vanX-vanY intergenic region of Tn1546 and an S183A mutation in the chromosomal d-alanyl:d-alanine ligase (Ddl). This substitution has been shown to be responsible for a drastic diminution of the affinity of the enzyme for d-Ala at subsite 1 in Escherichia coli DdlB. VRSA-11B exhibited an additional mutation, P216T, in the transcriptional regulator VanR, most probably associated with constitutive expression of vancomycin resistance. It is thus likely that VRSA-11B is a constitutive derivative of VRSA-11A selected during prolonged vancomycin therapy. Synthesis of peptidoglycan precursors ending in d-Ala-d-lactate was responsible for oxacillin susceptibility of VRSA-11A and VRSA-11B despite the presence of a wild-type mecA gene in both strains.
The carbapenemase-encoding blaKPC gene, which is rapidly spreading in Gram-negative rods, is located on a Tn3-based transposon, Tn4401, which carries a polymorphic region giving rise to five isoforms (a, b, c, d, and e) that is located immediately upstream of the blaKPC gene and thus likely involved in its expression. Using 5′ rapid amplification of cDNA ends (5′RACE), we identified three potential promoter sequences (P1, P2, and P3) upstream of the blaKPC gene, of which only P1 (absent from isoforms c and d) and P2 (present in all isoforms, with a −35 box located inside the right inverted repeat of ISKpn7) were shown to be true promoters involved in expression. One representative of each different promoter combination of Tn4401, i.e., P2 alone (isoform c), P1-P2 (isoform a), and P1-P2-P3 (isoform b), was cloned into an Escherichia coli plasmid vector. Using reverse transcription-PCR (RT-PCR), the highest level of expression was obtained with isoform a (P1 and P2), which is also the most commonly encountered form in enterobacterial clinical isolates, followed by isoforms b (P1, P2, and P3) and c (P2 only). These differences in expression led to slight differences in MIC values of carbapenems. In silico analysis of the DNA sequence of isoform b revealed a stem-loop structure that is likely responsible for strong stops observed in 5′RACE experiments and for decreased expression compared to that with isoform a (P1 and P2). In addition, such structures could also be at the origin for the deletions observed in isoforms a and c. Taken together, these results indicate that the P1 and P2 promoters both contribute to the expression of the blaKPC gene and that the construct with the highest level of expression is that possessing isoform a, which is also the most commonly encountered form in clinical isolates.
Solid-state micropores have been widely employed for 6 decades to recognize and size flowing unlabeled cells. However, the resistive-pulse technique presents limitations when the cells to be differentiated have overlapping dimension ranges such as B and T lymphocytes. An alternative approach would be to specifically capture cells by solid-state micropores. Here, the inner wall of 15-µm pores made in 10 µm-thick silicon membranes was covered with antibodies specific to cell surface proteins of B or T lymphocytes. The selective trapping of individual unlabeled cells in a bio-functionalized micropore makes them recognizable just using optical microscopy.
We locally deposited oligodeoxynucleotide (ODN) and ODN-conjugated antibody probes on the inner wall of the micropores by forming thin films of polypyrrole-ODN copolymers using contactless electro-functionalization. The trapping capabilities of the bio-functionalized micropores were validated using optical microscopy and the resistive-pulse technique by selectively capturing polystyrene microbeads coated with complementary ODN. B or T lymphocytes from a mouse splenocyte suspension were specifically immobilized on micropore walls functionalized with complementary ODN-conjugated antibodies targeting cell surface proteins.
The results showed that locally bio-functionalized micropores can isolate target cells from a suspension during their translocation throughout the pore, including among cells of similar dimensions in complex mixtures.
We recently completed a strategic planning process to better understand the development of our five-year-old PBRN and to identify gaps between our original vision and current progress. While many of our experiences are not new to the PBRN community, our reflections may be valuable for those developing or re-shaping PBRNs in a changing health care environment.
We learned about the importance of: (1) Shared vision and commitment to a unique patient population; (2) Strong leadership, mentorship, and collaboration; (3) Creative approaches to engaging busy clinicians and bridging the worlds of academia and community practice; (4) Harnessing data from electronic health records and navigating processes related to data protection, sharing, and ownership.
We must emphasize research that is timely, relevant, and integrated into practice. One model supporting this goal involves a broader partnership than was initially envisioned for our PBRN, one which includes clinicians, researchers, information architects and quality improvement experts partnering to develop an Innovation Center. This Center could facilitate development of relevant research questions while also addressing ‘quick-turnaround’ needs.
Gaps remain between our PBRN’s initial vision and current reality. Closing these gaps may require future creativity in partnership building and nontraditional funding sources.
practice-based research; community health; primary care; electronic health records; health care safety net
Effective therapeutic strategies are available to prevent adverse outcomes in patients with chronic kidney disease (CKD) but their clinical results are hindered by unplanned implementation. Coordination of care emerges as a suitable way to improve patient outcomes. In this study, we evaluated the effect of planned and coordinated patient management within a dedicated renal care network comparatively to standard renal care delivered in nephrology departments of teaching hospitals.
This observational matched cohort study included 40 patients with CKD stage 4–5 in the network group as compared with a control group of 120 patients matched for age, sex and diabetic status. Main outcome was a composite endpoint of death from cardiovascular cause and cardiovascular events during the first year after dialysis initiation.
There was no difference between the two groups neither for the primary outcome (40% vs 41%) nor for the occurrence of death from cardiovascular cause or cardiovascular events. Whereas the proportion of patients requiring at least one hospitalization was identical (83.3% vs 75%), network patients experienced less individual hospitalizations than control patients (2.3±2.0 vs 1.6±1.7) during the year before dialysis start. Patients of the network group had a slower renal function decline (7.7±2.5 vs 4.9±1.1 ml/min/1,73m2 per year; p=0.04).
In this limited series of patients, we were unable to demonstrate a significant impact of the coordinated renal care provided in the network on early cardiovascular events in incident dialysis patients. However, during the predialysis period, there were less hospitalizations and a slower slope of renal function decrease.
Chronic kidney disease; Multidisciplinary intervention; Renal cares network; Cardiovascular events; CKD progression
The Feline Immunodeficiency Virus (FIV) capsid protein p24 oligomerizes to form a closed capsid that protects the viral genome. Because of its crucial role in the virion, FIV p24 is an interesting target for the development of therapeutic strategies, although little is known about its structure and assembly. We defined and optimized a protocol to overexpress recombinant FIV capsid protein in a bacterial system. Circular dichroism and isothermal titration calorimetry experiments showed that the structure of the purified FIV p24 protein was comprised mainly of α-helices. Dynamic light scattering (DLS) and cross-linking experiments demonstrated that p24 was monomeric at low concentration and dimeric at high concentration. We developed a protocol for the in vitro assembly of the FIV capsid. As with HIV, an increased ionic strength resulted in FIV p24 assembly in vitro. Assembly appeared to be dependent on temperature, salt concentration, and protein concentration. The FIV p24 assembly kinetics was monitored by DLS. A limit end-point diameter suggested assembly into objects of definite shapes. This was confirmed by electron microscopy, where FIV p24 assembled into spherical particles. Comparison of FIV p24 with other retroviral capsid proteins showed that FIV assembly is particular and requires further specific study.
Recent advances in the identification of susceptibility genes and environmental exposures provide broad support for a post-infectious autoimmune basis for narcolepsy/hypocretin (orexin) deficiency. We genotyped loci associated with other autoimmune and inflammatory diseases in 1,886 individuals with hypocretin-deficient narcolepsy and 10,421 controls, all of European ancestry, using a custom genotyping array (ImmunoChip). Three loci located outside the Human Leukocyte Antigen (HLA) region on chromosome 6 were significantly associated with disease risk. In addition to a strong signal in the T cell receptor alpha (TRA@), variants in two additional narcolepsy loci, Cathepsin H (CTSH) and Tumor necrosis factor (ligand) superfamily member 4 (TNFSF4, also called OX40L), attained genome-wide significance. These findings underline the importance of antigen presentation by HLA Class II to T cells in the pathophysiology of this autoimmune disease.
While there is now broad consensus that narcolepsy-hypocretin deficiency results from a highly specific autoimmune attack on hypocretin cells, little is understood regarding the initiation and progression of the underlying autoimmune process. We have taken advantage of a unique high-density genotyping platform (the ImmunoChip) designed to study variants in genes known to be important to autoimmune and inflammatory diseases. Our study of nearly 2000 narcolepsy cases compared to 10,000 controls underscored important roles for HLA DQB1*06:02 and the T cell receptor alpha genes and implicated two additional genes, Cathepsin H and TNFSF4/OX40L, in disease pathogenesis. These findings are particularly important, as these encoded proteins have key roles in antigen processing, presentation, and T cell response, and they suggest that specific interactions at the immunological synapse constitute the pathway to the disease. Further studies of these genes and encoded proteins may therefore reveal the mechanism leading to this highly selective and unique autoimmune disease.
In bacteria, transformation and restriction-modification (R-M) systems play potentially antagonistic roles. While the former, proposed as a form of sexuality, relies on internalized foreign DNA to create genetic diversity, the latter degrade foreign DNA to protect from bacteriophage attack. The human pathogen Streptococcus pneumoniae is transformable and possesses either of two R-M systems, DpnI and DpnII, which respectively restrict methylated or unmethylated double-stranded (ds) DNA. S. pneumoniae DpnII strains possess DpnM, which methylates dsDNA to protect it from DpnII restriction, and a second methylase, DpnA, which is induced during competence for genetic transformation and is unusual in that it methylates single-stranded (ss) DNA. DpnA was tentatively ascribed the role of protecting internalized plasmids from DpnII restriction, but this seems unlikely in light of recent results establishing that pneumococcal transformation was not evolved to favor plasmid exchange. Here we validate an alternative hypothesis, showing that DpnA plays a crucial role in the protection of internalized foreign DNA, enabling exchange of pathogenicity islands and more generally of variable regions between pneumococcal isolates. We show that transformation of a 21.7 kb heterologous region is reduced by more than 4 logs in dpnA mutant cells and provide evidence that the specific induction of dpnA during competence is critical for full protection. We suggest that the integration of a restrictase/ssDNA-methylase couplet into the competence regulon maintains protection from bacteriophage attack whilst simultaneously enabling exchange of pathogenicicy islands. This protective role of DpnA is likely to be of particular importance for pneumococcal virulence by allowing free variation of capsule serotype in DpnII strains via integration of DpnI capsule loci, contributing to the documented escape of pneumococci from capsule-based vaccines. Generally, this finding is the first evidence for a mechanism that actively promotes genetic diversity of S. pneumoniae through programmed protection and incorporation of foreign DNA.
Natural genetic transformation can compensate for the absence of sexual reproduction in bacteria, allowing genetic diversification by recombination. It proceeds through the internalization of single stranded (ss) DNA fragments created from an exogenous double stranded (ds) DNA substrate, which are incorporated into the genome by homology. On the other hand, restriction-modification (R-M) systems, which protect bacteria from bacteriophage attack by degrading invading foreign DNA, potentially antagonize transformation. About half of the strains of the naturally transformable species and human pathogen Streptococcus pneumoniae possess an R-M system, DpnII, restricting unmethylated dsDNA. DpnII strains possess DpnA which is unusual in that it methylates ssDNA. Here we show that DpnA plays a crucial role in the protection of internalized heterologous transforming ssDNA, preventing the post-replicative destruction by DpnII of transformants produced by chromosomal integration of heterogolous DNA by virtue of flanking homology. This protective role of DpnA is of particular importance for acquisition of pathogenicity islands, such as capsule loci, from non-DpnII origin by DpnII strains, likely contributing to pneumococcal virulence via escape from capsule-based vaccines. Generally, this finding is the first evidence for a mechanism that actively promotes genetic diversity of S. pneumoniae through active protection and incorporation of foreign DNA.