Role of LFA-1, ICAM-1, VLA-4 and VCAM-1 in lymphocyte migration across retinal pigment epithelial monolayers in vitro.

The blood-retinal barrier (BRB), which is composed of the retinal pigment epithelium (RPE) and retinal vascular endothelium, normally restricts the traffic of lymphocytes into the retina. During ocular inflammatory conditions such as posterior uveitis there is a large increase in lymphocyte migration across the BRB. The differential role played by the two barrier sites, however, remains unclear. To evaluate the role of the posterior BRB, the migration of CD4+ antigen-specific T-cell line through rat RPE cell monolayers was investigated in vitro using time-lapse videomicroscopy. The adhesion molecules involved in controlling transepithelial migration across normal and interferon-gamma (IFN-gamma)-activated RPE was assessed with monoclonal antibodies directed against cell adhesion molecules. Lymphocytes were treated with antibodies specific for CD11a (alpha L subunit of LFA-1), CD18 (beta 2 subnit of the leucam family) and CD49 d (alpha 4 subnit of very late activation antigen-4, VLA-4), and the RPE with antibodies specific for CD54 (intracellular adhesion molecule-1, ICAM-1) and CD 106 (vascular cell adhesion molecule-1, VCAM-1). Migration across unstimulated RPE was inhibited by antibodies to ICAM-1 (48.6 +/- 3.5% reduction), leucocyte functional antigen-1 (LFA-1) alpha (61 +/- 5.2%) and LFA-1 beta (63.2 +/- 4.7%), but not by antibodies to VLA-4. VCAM-1 was not expressed on untreated RPE. Following activation of the RPE monolayers for 72 hr with IFN-gamma, antibodies to LFA-1 alpha, LFA-1 beta and ICAM-1 inhibited migration by 49.9 +/- 9.4%, 63.6 +/- 5.5% and 47.7 +/- 4.2% respectively. Antibodies to VLA-4 and VCAM-1 blocked migration by 21.5 +/- 8.4% and 32.3 +/- 6.2%, respectively, which correlated with the induction of VCAM-1 expression on RPE and increased migration. Under these conditions blocking both VCAM-1 and ICAM-1 reduced migration by 70.9 +/- 2.3%, which was greater than the effect of blocking either of these molecules alone. These results demonstrate that the posterior barrier of the BRB utilizes the same principle receptor-ligand pairings in controlling lymphocyte traffic into the retina as the vascular endothelium of the anterior BRB.     

Effect of temperature on growth, hemagglutination, and protease activity of Porphyromonas gingivalis

Bacteria persisting in periodontal pockets are exposed to elevated temperatures during periods of inflammation. Temperature is an environmental factor that can modulate gene expression. Consequently, in the present study we examined the effect of temperature on the expression of virulence determinants by the periodontopathogen, Porphyromonas gingivalis. P. gingivalis W50 was grown in a complex medium under hemin excess at pH 7.0 and at a constant temperature of either 37, 39, or 41 degrees C; cultures were monitored for protease and hemagglutinin activity. P. gingivalis grew well at all three temperatures. An increase in growth temperature from 37 to 39 degrees C resulted in a 65% reduction in both total arginine- and lysine-specific activities (P < 0.01). A further rise in growth temperature to 41 degrees C led to even greater reductions in arginine-specific (82%; P < 0.001) and lysine-specific (73%; P < 0. 01) activities. These reductions were also associated with an altered distribution of individual arginine-specific enzyme isoforms. At 41 degrees C, there was a disproportionate reduction in the level of the heterodimeric RI protease, which also contains adhesin domains. The reduction also correlated with a markedly diminished hemagglutination activity of cells, especially in those grown at 41 degrees C, and a reduced immunoreactivity with a monoclonal antibody which recognizes gene products involved in hemagglutination. Thus, as the environmental temperature increased, P. gingivalis adopted a less aggressive phenotype, while retaining cell population levels. The coordinate down-regulation of virulence gene expression in response to an environmental cue linked to the intensity of the host inflammatory response is consistent with the clinically observed cyclical nature of disease progression in periodontal diseases.     

Natural genetic variation caused by small insertions and deletions in the human genome

Human genetic variation is expected to play a central role in personalized medicine. Yet only a fraction of the natural genetic variation that is harbored by humans has been discovered to date. Here we report almost 2 million small insertions and deletions (INDELs) that range from 1 bp to 10,000 bp in length in the genomes of 79 diverse humans. These variants include 819,363 small INDELs that map to human genes. Small INDELs frequently were found in the coding exons of these genes, and several lines of evidence indicate that such variation is a major determinant of human biological diversity. Microarray-based genotyping experiments revealed several interesting observations regarding the population genetics of small INDEL variation. For example, we found that many of our INDELs had high levels of linkage disequilibrium (LD) with both HapMap SNPs and with high-scoring SNPs from genome-wide association studies. Overall, our study indicates that small INDEL variation is likely to be a key factor underlying inherited traits and diseases in humans.     

Dorsal lunate tilt (DISI configuration): sign of scaphoid fracture displacement

Excessive dorsiflexion (dorsal tilting) of the lunate on a lateral wrist radiograph can be an important sign of carpal injury. Lunate dorsiflexion is a well-recognized sign of an intercarpal ligamentous injury pattern known as dorsal intercalated segment instability (DISI). It is less well recognized that excessive dorsal tilting of the lunate (DISI configuration) can also be produced by displacement of a scaphoid waist fracture. Since the management and prognosis of displaced scaphoid fractures may be quite different from those for nondisplaced fractures, radiologists can make an important contribution by recognizing dorsal tilting of the lunate and appreciating that it may be an important, indirect sign of scaphoid fracture displacement, which may not be directly visualized with standard wrist radiography. In this setting, computed tomography or complex motion tomography may be helpful for further evaluation of the scaphoid fracture.     

A hot L1 retrotransposon evades somatic repression and initiates human colorectal cancer

Although human LINE-1 (L1) elements are actively mobilized in many cancers, a role for somatic L1 retrotransposition in tumor initiation has not been conclusively demonstrated. Here, we identify a novel somatic L1 insertion in the APC tumor suppressor gene that provided us with a unique opportunity to determine whether such insertions can actually initiate colorectal cancer (CRC), and if so, how this might occur. Our data support a model whereby a hot L1 source element on Chromosome 17 of the patient''s genome evaded somatic repression in normal colon tissues and thereby initiated CRC by mutating the APC gene. This insertion worked together with a point mutation in the second APC allele to initiate tumorigenesis through the classic two-hit CRC pathway. We also show that L1 source profiles vary considerably depending on the ancestry of an individual, and that population-specific hot L1 elements represent a novel form of cancer risk.Human LINE-1 (L1) elements are autonomous retrotransposons that continue to produce new “offspring” L1 insertions in human genomes (Beck et al. 2010, 2011; Ewing and Kazazian 2010; Huang et al. 2010; Iskow et al. 2010; Stewart et al. 2011; The 1000 Genomes Project Consortium 2015; Sudmant et al. 2015). Until recently, L1 elements were thought to be mobilized primarily in the germline and then silenced in somatic cells throughout adulthood. However, several recent reports have shown that L1 elements are active in at least some adult somatic tissues, including the brain (Muotri et al. 2005; Coufal et al. 2009; Baillie et al. 2011; Evrony et al. 2012; Upton et al. 2015) and epithelial somatic tumors (Miki et al. 1992; Iskow et al. 2010; Lee et al. 2012; Solyom et al. 2012; Shukla et al. 2013; Helman et al. 2014; Tubio et al. 2014; Doucet-O''Hare et al. 2015; Ewing et al. 2015; Rodic et al. 2015). These observations have led to the suggestion that L1 might play a role in initiating human cancers by mutating specific oncogenes or tumor suppressor genes in somatic cells.However, several broad surveys of somatic L1 insertions in human cancers have detected only a few strong L1 driver candidates (Lee et al. 2012; Shukla et al. 2013; Helman et al. 2014; Tubio et al. 2014), and it is unclear whether any of these insertions could have initiated tumorigenesis in the cancers in which they were discovered (see Discussion). Thus, somatic L1 drivers that affect the earliest stages of tumorigenesis have been elusive in these studies, and it is presently unclear whether L1 has the capacity to initiate tumorigenesis in somatic cells. This could, in principle, reflect a lack of knowledge of the oncogenes and tumor suppressor genes that act at the earliest stages of tumorigenesis in human cancers. However, it might instead indicate that L1 elements are not generally capable of initiating tumorigenesis in somatic cells because they are effectively repressed in most cells. An alternative possibility is that somatic L1 mobilization generally occurs only after an L1-permissive environment is established in an emerging tumor. Under this scenario, L1 could not actually initiate tumorigenesis but might instead become active during the more advanced stages of tumor progression and metastasis (e.g., Rodic et al. 2015).In perhaps the strongest study implicating L1 in tumor initiation thus far, a somatic L1 insertion was identified in a case of colorectal cancer (CRC) that disrupted the APC tumor suppressor gene (Miki et al. 1992). The APC gene is the earliest gatekeeper that is mutated in the majority (∼85%) of CRC cases and, in fact, both copies of APC must be mutated to initiate CRC through this classic two-hit pathway (Kinzler and Vogelstein 1996; Fearon 2011). In the case of familial adenomatous polyposis (FAP) and other CRC syndromes, one mutated copy of APC is inherited in the germline, and the other is acquired during the lifetime of the individual. In the sporadic form of the disease, both copies of APC must be mutated independently in a somatic cell in order to initiate tumorigenesis (Kinzler and Vogelstein 1996; Fearon 2011). In the remaining 15% of CRC cases, tumorigenesis is instead initiated by a hypermutation phenotype that is associated with microsatellite instability (MSI) and faulty DNA repair (Fearon 2011). APC also can be mutated in this less common form of MSI-CRC, but it does not promote the earliest stages of tumor initiation in such cases.Although one of the two APC alleles clearly was disrupted by L1 in the sporadic case of CRC described by Miki et al. (1992), the status of the second APC allele was not investigated in that study. Furthermore, the MSI phenotype of the tumor was not investigated, leaving open the possibility that tumorigenesis was initiated by a hypermutation phenotype associated with faulty DNA repair, rather than by the more common pathway involving biallelic mutations in APC (Fearon 2011). It also is unclear how the L1 insertion in APC could have been generated sufficiently early to initiate tumorigenesis in a normal colon cell. Thus, many questions remain unanswered as to the genesis of this somatic L1 insertion in APC and its impact on tumorigenesis (Miki et al. 1992).     

Making Quality Health Websites a National Public Health Priority: Toward Quality Standards

BackgroundMost US adults have limited health literacy skills. They struggle to understand complex health information and services and to make informed health decisions. The Internet has quickly become one of the most popular places for people to search for information about their health, thereby making access to quality information on the Web a priority. However, there are no standardized criteria for evaluating Web-based health information. Every 10 years, the US Department of Health and Human Services'' Office of Disease Prevention and Health Promotion (ODPHP) develops a set of measurable objectives for improving the health of the nation over the coming decade, known as Healthy People. There are two objectives in Healthy People 2020 related to website quality. The first is objective Health Communication and Health Information Technology (HC/HIT) 8.1: increase the proportion of health-related websites that meet 3 or more evaluation criteria for disclosing information that can be used to assess information reliability. The second is objective HC/HIT-8.2: increase the proportion of health-related websites that follow established usability principles.ObjectiveThe ODPHP conducted a nationwide assessment of the quality of Web-based health information using the Healthy People 2020 objectives. The ODPHP aimed to establish (1) a standardized approach to defining and measuring the quality of health websites; (2) benchmarks for measurement; (3) baseline data points to capture the current status of website quality; and (4) targets to drive improvement.MethodsThe ODPHP developed the National Quality Health Website Survey instrument to assess the quality of health-related websites. The ODPHP used this survey to review 100 top-ranked health-related websites in order to set baseline data points for these two objectives. The ODPHP then set targets to drive improvement by 2020.ResultsThis study reviewed 100 health-related websites. For objective HC/HIT-8.1, a total of 58 out of 100 (58.0%) websites met 3 or more out of 6 reliability criteria. For objective HC/HIT-8.2, a total of 42 out of 100 (42.0%) websites followed 10 or more out of 19 established usability principles. On the basis of these baseline data points, ODPHP set targets for the year 2020 that meet the minimal statistical significance—increasing objective HC/HIT-8.1 data point to 70.5% and objective HC/HIT-8.2 data point to 55.7%.ConclusionsThis research is a critical first step in evaluating the quality of Web-based health information. The criteria proposed by ODPHP provide methods to assess website quality for professionals designing, developing, and managing health-related websites. The criteria, baseline data, and targets are valuable tools for driving quality improvement.     

Antigen presentation by macrophages is enhanced by the uptake of necrotic, but not apoptotic, cells

The aim of this study was to determine whether phagocytosis of necrotic or apoptotic cells affects antigen presentation by murine bone marrow-derived macrophages. After uptake of necrotic neutrophils, macrophages were able to stimulate significantly higher T cell proliferation in vitro against both the recall antigen albumin and the mitogen concanavalin A. No such effect was seen following phagocytosis of apoptotic neutrophils. Flow cytometry revealed that, within 4h of ingestion, macrophages that had taken up the necrotic cells expressed higher levels of CD40 than those that had phagocytosed apoptotic cells. Macrophage cultures pulsed with apoptotic, but not necrotic, neutrophils contained higher levels of transforming growth factor beta1, but lower concentrations of tumour necrosis factor alpha, compared to untreated controls. Our interpretation of these results is that macrophages that have taken up necrotic neutrophils co-stimulate T cells with greater efficiency due to rapid CD40 up-regulation, whereas those that have ingested apoptotic cells are not only ineffective in co-stimulation, but also secrete inhibitory cytokine.     

Structural genomic variation in childhood epilepsies with complex phenotypes

A genetic contribution to a broad range of epilepsies has been postulated, and particularly copy number variations (CNVs) have emerged as significant genetic risk factors. However, the role of CNVs in patients with epilepsies with complex phenotypes is not known. Therefore, we investigated the role of CNVs in patients with unclassified epilepsies and complex phenotypes. A total of 222 patients from three European countries, including patients with structural lesions on magnetic resonance imaging (MRI), dysmorphic features, and multiple congenital anomalies, were clinically evaluated and screened for CNVs. MRI findings including acquired or developmental lesions and patient characteristics were subdivided and analyzed in subgroups. MRI data were available for 88.3% of patients, of whom 41.6% had abnormal MRI findings. Eighty-eight rare CNVs were discovered in 71 out of 222 patients (31.9%). Segregation of all identified variants could be assessed in 42 patients, 11 of which were de novo. The frequency of all structural variants and de novo variants was not statistically different between patients with or without MRI abnormalities or MRI subcategories. Patients with dysmorphic features were more likely to carry a rare CNV. Genome-wide screening methods for rare CNVs may provide clues for the genetic etiology in patients with a broader range of epilepsies than previously anticipated, including in patients with various brain anomalies detectable by MRI. Performing genome-wide screens for rare CNVs can be a valuable contribution to the routine diagnostic workup in patients with a broad range of childhood epilepsies.     

Evaluation of a commercial enzyme-linked immunosorbent assay for detection of immunoglobulin M antibody in diagnosis of human leptospiral infection.

The PanBio Leptospira immunoglobulin M (IgM) enzyme-linked immunosorbent assay (ELISA) is a commercially available screening test for the diagnosis of acute leptospiral infection. The ability of the test to diagnose early or recent Leptospira interrogans infection was assessed by testing sera with known microagglutination test (MAT) titers to serovars pomona, hardjo, copenhageni, and australis. The IgM ELISA detected all 41 cases of early or recent leptospiral infection (sensitivity, 100%), with a positive ELISA result seen in many cases before MAT antibody titers reached 1:50. Thirty-eight of 41 patients showed seroconversion (fourfold or greater increase in titer by MAT, 2 of 41 patients had a single sample with elevated titer, and 1 patient from whom leptospires were isolated from a blood sample failed to show MAT titers, despite a seroconversion (negative to positive result) in the ELISA. Follow-up sera obtained from 8 of 12 patients (67%) for 3 to 48 months after the acute stage of illness showed persisting IgM antibody. However, the range of levels detected in these samples (maximum ELISA ratio, 2.0) was lower than the range seen when infection was recent. Reactivity in the IgM ELISA was observed for only 1 of 59 serum samples from asymptomatic donors (specificity, 98%) and 16 of 233 serum samples from patients with Ross River virus, brucella, Epstein-Barr virus, cytomegalovirus, mycoplasma, Q-fever, toxoplasma, hepatitis A virus, Treponema pallidum, or Borrelia burgdorferi infection (specificity, 93%), with the majority of these patients showing lower levels of IgM in comparison to those in patients with leptospiral infection. We conclude that this ELISA is sufficiently sensitive for use as an initial screen for leptospiral infections, with subsequent confirmation of positive test results by MAT.     

The GAP-related domain of tuberin, the product of the TSC2 gene, is a target for missense mutations in tuberous sclerosis

Tuberous sclerosis is an autosomal dominant trait in which the dysregulation of cellular proliferation and differentiation results in the development of hamartomatous growths in many organs. The TSC2 gene is one of two genes determining tuberous sclerosis. Inactivating germline mutations of TSC2 in patients with tuberous sclerosis and somatic loss of heterozygosity at the TSC2 locus in the associated hamartomas indicate that TSC2 functions as a tumour suppressor gene and that loss of function is critical to expression of the tuberous sclerosis phenotype. The TSC2 product, tuberin, has a region of homology with the GTPase activating protein rap1GAP and stimulates the GTPase activity of rap1a and rab5a in vitro. Here we show that the region of homology between tuberin and human rap1GAP and the murine GAP mSpa1 is more extensive than previously reported and spans approximately 160 amino acid residues encoded within exons 34-38 of the TSC2 gene. Single strand conformation polymorphism analysis of these exons in 173 unrelated patients with tuberous sclerosis and direct sequencing of variant conformers together with study of additional family members enabled characterisation of disease associated mutations in 14 cases. Missense mutations, which occurred in exons 36, 37 and 38 were identified in eight cases, four of whom shared the same recurrent change P1675L. Each of the five different missense mutations identified was shown to occur de novo in at least one sporadic case of tuberous sclerosis. The high proportion of missense mutations detected in the region of the TSC2 gene encoding the GAP-related domain supports its key role in the regulation of cellular growth.