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BackgroundEye movement abnormalities are paramount in neurological disorders. However, unaided eye movement assessments lack granularity. Although videooculography (VOG) improves diagnostic accuracy, resource intensiveness preclude its broad use. To bridge this care gap, we here validate a framework for smartphone video-based nystagmography capitalizing on recent computer vision advances.MethodsA recurrent convolutional network was fine-tuned for pupil tracking using >550 annotated frames: ConVNG. Slow phase velocity of optokinetic nystagmus was calculated in 10 subjects using both ConVNG and VOG. Equivalence of accuracy and precision was assessed using the “two one-sample t-test” (TOST) and Bayesian interval-null approaches.ResultsConVNG tracking accuracy reached 9-15% of an average pupil diameter. SPV measurement accuracy was equivalent to VOG (p< .017; Bayes factors (BF) > 24). Average precision was 0.30° for ConVNG and 0.12° for VOG.ConclusionsConVNG enables smartphone video nystagmography with an accuracy comparable to VOG and precision approximately one order of magnitude higher than comparable ARKit applications. This serves as a blueprint for highly accessible tools with potential to accelerate progress toward precise and personalized Medicine.

The existence of surface waves on anisotropic materials was proven under fairly general conditions by Lothe and Barnett in 1976 [1]. But, until now, the status of surface waves on piezoelectric materials has remained unresolved. This paper presents general existence theorems for surface waves on piezoelectric substrates. It is demonstrated that for short circuit boundary conditions a surface wave solution must exist under virtually any circumstances. However, for a free surface, comparatively stringent existence conditions are required. Numerical examples are given for both free and shorted surfaces, and it is demonstrated that, in some situations, a surface wave solution may not exist for free surface propagation. The existence proofs were developed as a result of theoretical work on Green function modeling, which is now the preferred technique for rigorous SAW and pseudo-SAW device analysis. The mechanisms of the existence proofs and the associated mathematical results give great insight into the structure and properties of the Green functions and include many results that are directly relevant to device analysis.

We tested the effects of blocking CD28-B7 T cell costimulation by using CTLA4Ig in an established transplantation model in which LBNF1 cardiac allografts are rejected in an accelerated manner (

Blockade of CD28-mediated T cell costimulatory signals produces effective immunosuppression of a variety of T cell-dependent in vivo immune responses, including autoimmune disorders and transplant rejection. The soluble fusion protein CTLA4Ig, which competitively blocks CD28 ligands B7-1 and B7-2, can prevent allograft and xenograft rejection and in some circumstances induce transplantation tolerance. To determine the relative roles of B7-1 and B7-2 in graft rejection, we have performed islet and cardiac allografts with normal and B7-1(-/-) mice in conjunction with selective blocking reagents. We found that the absence of B7-1 on donor or recipient tissues leads to a slight prolongation of islet allograft survival, but has minimal or no effect on cardiac allograft survival. Allograft function is further prolonged in the islet model when both donor and recipient lack B7-1, although cardiac allograft survival is not prolonged. In the cardiac model, treatment with CTLA4Ig induces long term survival in B7-1(-/-) recipients regardless of donor status. In contrast, anti-B7-2 mAb leads to indefinite allograft survival only when the recipient and donor both lack B7-1, indicating that even in the absence of available B7-2, B7-1 molecules on the donor or recipient cells alone are sufficient to induce graft rejection. These data also indicate that B7-1 and B7-2 are the only CD28 ligands relevant to cardiac allograft rejection in mice.

A linear programming algorithm is proposed for designing surface acoustic wave (SAW) filters or filterbanks with arbitrary amplitude and phase responses. A modified sampling theorem representation is employed for the transducer frequency responses which allows the number of independent variables to be minimized without degrading the filter characteristics. The method can also be used as part of an iterative procedure to generate optimal corrections for second order effects such as diffraction and circuit loading. A simplified algorithm for this procedure is given, and the method is illustrated with theoretical and experimental data from a three channel contiguous SAW filterbank design. Although the method given in this paper is formulated primarily for SAW filters, it is equally applicable to FIR digital filter design. >

CD44 is implicated in the regulation of tumor growth and metastasis but the mechanism by which expression of different CD44 isoforms determines the rate of primary and secondary tumor growth remains unclear. In the present study we use a human melanoma transfected with wild-type and mutant forms of CD44 to determine which functional property of the CD44 molecule is critical in influencing tumor behavior. We show that expression of a wild-type CD44 isoform that binds hyaluronic acid augments the rapidity of tumor formation by melanoma cells in vivo, whereas expression of a CD44 mutant, which does not mediate cell attachment to hyaluronate, fails to do so. The importance of CD44-hyaluronate interaction in tumor development is underscored by the differential inhibitory effect of soluble wild-type and mutant CD44-Ig fusion proteins on melanoma growth in vivo. Whereas local administration of a mutant, nonhyaluronate binding, CD44-Ig fusion protein has no effect on subcutaneous melanoma growth in mice, infusion of wild-type CD44-Ig is shown to block tumor development. Taken together, these observations suggest that the tumor growth promoting property of CD44 is largely dependent on its ability to mediate cell attachment to hyaluronate.

T cell surface receptors CD28 and CTLA-4 are homologous members of the immunoglobulin superfamily (IgSF), each comprising a single V-like extracellular domain. CD28 and CTLA-4 bind to the B7-1 and B7-2 counter-receptors on antigen presenting cells (APCs), thereby triggering a costimulatory pathway important for optimal T cell activation in vitro and in vivo. Soluble forms of CD28 and CTLA-4 in which the V-like extracellular domains were fused to Ig constant domains (CD28Ig and CTLA4Ig), have been used to study their interactions with B7-1 and B7-2, with CTLA4Ig binding B7-1 more strongly than CD28Ig (approximately 20-fold higher avidity). We have now, by site-specific and homologue mutagenesis, identified regions in CTLA4Ig important for strong binding to B7-1. A hexapeptide motif (MYPPPY) in the complementarity determining region 3 (CDR3)-like region is fully conserved in all CD28 and CTLA-4 family members. Alanine scanning mutagenesis through the motif in CTLA4Ig and at selected residues in CD28Ig reduced or abolished binding to B7-1. Chimeric molecules HS4, HS4-A, and HS4-B were constructed in which CDR3-like regions of CTLA-4, COOH-terminally extended to include nonconserved residues, were grafted onto CD28Ig. These homologue mutants showed stronger binding to B7-1 than did CD28Ig. Grafting of the CDR1-like region of CTLA-4, which is not conserved in CD28 and is predicted to be spatially adjacent to CDR3, into HS4 and HS4-A, resulted in chimeric molecules (HS7 and HS8) which bound B7-1 even better. Inclusion of the CDR2-like domain of CTLA-4 into HS7 and HS8 did not further increase binding. Thus, the MYPPPY motifs of CTLA4Ig and CD28Ig are important for their binding to B7-1, but the increased strength of this binding by CTLA4Ig is mediated by nonconserved residues in the CDR1- and CDR3-analogous regions.

The recently isolated 4-1BB cDNA clone encodes a cell surface protein expressed by activated T cells. Its extracellular domain is homologous to members of the nerve growth factor receptor super family and its cytoplasmic domain contains a sequence homologous to the binding site for the T-cell-specific tyrosine kinase p56lck found in the cytoplasmic domains of CD4 and CD8 alpha. At present the function of 4-1BB is not known. We prepared a 4-1BB-immunoglobulin fusion protein (4-1BB Rg). This protein was used in immunohistochemical studies to identify tissues that express the 4-1BB ligand. 4-1BB Rg bound to virtually all tissues examined, suggesting that extracellular components might function as its ligands. To explore this possibility, 4-1BB was expressed in COS cells and found to mediate the binding of fibronectin, vitronectin, laminin, and collagen VI but not of collagen I. The binding of extracellular matrix proteins to 4-1BB was not mediated by Arg-Gly-Asp (RGD) or CS-1 amino acid sequences. Experiments with overlapping proteolytic fragments of fibronectin showed that 4-1BB interacts with multiple regions of fibronectin. The interaction between extracellular matrix proteins and 4-1BB was completely blocked by the anionic carbohydrate polymer fucoidan and was partially blocked by the anionic carbohydrate polymer dextran sulfate and the glycosaminoglycan heparin sulfate but was unaffected by desulfated heparin. These results suggest that carbohydrates may play a role in mediating the 4-1BB-extracellular matrix protein adhesion.

Background Tobacco smoking during pregnancy is known to adversely affect development of the central nervous system in babies of smoking mothers by restricting utero–placental blood flow and the amount of oxygen available to the fetus. Behavioral data associate maternal smoking with lower verbal scores and poorer performance on specific language/auditory tests. Objectives In the current study we examined the effects of maternal smoking during pregnancy on newborns’ speech processing ability as measured by event-related potentials (ERPs). Method High-density ERPs were recorded within 48 hr of birth in healthy newborn infants of smoking (n = 8) and nonsmoking (n = 8) mothers. Participating infants were matched on sex, gestational age, birth weight, Apgar scores, mother’s education, and family income. Smoking during pregnancy was determined by parental self-report and medical records. ERPs were recorded in response to six consonant–vowel syllables presented in random order with equal probability. Results Brainwaves of babies of nonsmoking mothers were characterized by typical hemisphere asymmetries, with larger amplitudes over the left hemisphere, especially over temporal regions. Further, infants of nonsmokers discriminated among a greater number of syllables whereas the newborns of smokers began the discrimination process at least 150 msec later and differentiated among fewer stimuli. Conclusions Our findings indicate that prenatal exposure to tobacco smoke in otherwise healthy babies is linked with significant changes in brain physiology associated with basic perceptual skills that could place the infant at risk for later developmental problems.

Provision of adequate T cell costimulation is critical for the development of acute and chronic allograft rejection. We have previously reported that early blockade of CD28-B7 T cell costimulation prevents the development of graft arteriosclerosis, in the LEW into F344 rat cardiac transplant model. In this study, we used the same model to examine the requirement for CD28-B7-mediated T cell costimulation in the progression of established chronic rejection and examined the individual roles of B7–1 (CD80) and B7–2 (CD86) costimulatory molecules. Late blockade of CD28-B7 T cell costimulation by the fusion protein CTLA4Ig, which binds both CD80 and CD86, attenuated the development of transplant arteriosclerosis, mononuclear cell infiltration, and parenchymal fibrosis in this model. Selective blockade of CD80 using the mutant fusion protein Y100F was as effective as CTLA4Ig in this regard. In contrast to CTLA4Ig, blockade of CD80 alone by Y100F was ineffective at preventing early graft loss and prolonging graft survival when given early after transplantation. This study is the first to demonstrate that late blockade of CD28-B7 T cell costimulation interrupts chronic cardiac allograft rejection, and it indicates the importance of continued T cell activation in this process. This study further defines functional differences between CD80 and CD86 costimulatory molecules in vivo.

TYLCV is a devastating whitefly-vectored disease of tomato that has spread from the Mediterranean to the Caribbean region including Florida. Along with cultural control, such as host free periods, insecticidal control of the vector is the key to present-day management of TYLCV. Greenhouse-raised seedlings were planted 9 Mar at 18-inch spacing on two sets of three drip irrigated beds, 240 ft long on 6-ft centers. The outer two beds of each set were divided into seven plots, each 34 ft long, and assigned to treatments in a CRB design with four replications. The middle row of each three-bed set was left untreated to serve as a source of whiteflies. On 16 Mar, two tomato plants that had been exposed to TYLCV infected whiteflies were transplanted in the center of each plot to provide a source of virus inoculum. Admire 2F and Platium 2 SC were applied as soil drenches on 13 Mar in 10 ml water per plant. Two treatments, one with the half rate of Admire and one with no Admire, received weekly applications, 11 in total, of Neemix beginning 1 Mar when the plants were still in the transplant trays. Actara 25 WG was applied as a foliar spray on 21 Mar, 11 Apr, and 2 May. Applaud 70 WP was applied 11 Apr and the same plots sprayed with Knack 0.86 EC on 2 May. Foliar applications were made using a high clearance sprayer driven by a hydraulic pump operating at 200 psi and delivering the spray through two drop booms equipped with two yellow hollow cone ceramic Albuz nozzles each at a rate of 44 gpa until 11 Apr when another nozzle was added to each drop for an output of 66 gpa for the remaining applications. Seven weekly evaluations of whitefly adults were made beginning 10 Apr by beating one side of four plants at four locations per plot with a 9 x 13-inch pie pan painted black and coated with a 9:1 mixture of vegetable oil and liquid detergent. Immature stages were monitored from one leaf removed from the 6th node of four centrally located plants in each plot. All whitefly stages were counted that appeared in a 2-cm2 ring placed four times on each leaflet using three leaflets from each leaf collected. Plants were monitored every 3 or 4 days for symptoms of TYLCV. On 26 May, 15 plants per plot were harvested and the number and weights of insect, disease, and marketable fruit were recorded.

Infection of C57BL/6 mice with Toxoplasma gondii leads to chronic encephalitis characterized by infiltration into the brain of T cells that produce IFN-gamma and mediate resistance to the parasite. Our studies revealed that expression of B7.1 and B7.2 was up-regulated in brains of mice with toxoplasmic encephalitis (TE). Because CD28/B7-mediated costimulation is important for T cell activation, we assessed the contribution of this interaction to the production of IFN-gamma by T cells from brains and spleens of mice with TE. Stimulation of splenocytes with Toxoplasma Ag or anti-CD3 mAb resulted in production of IFN-gamma, which was inhibited by 90% in the presence of CTLA4-Ig, an antagonist of B7 stimulation. However, production of IFN-gamma by T cells from the brains of these mice was only slightly reduced (20%) by the addition of CTLA4-Ig. To address the role of the CD28/B7 interaction during TE, we compared the development of disease in C57BL/6 wild-type (wt) and CD28-/- mice. Although the parasite burden was similar in wt and CD28-/- mice, CD28-/- mice developed less severe encephalitis and survived longer than wt mice. Ex vivo recall responses revealed that mononuclear cells isolated from the brains of chronically infected CD28-/- mice produced less IFN-gamma than wt cells, and this correlated with reduced numbers of intracerebral CD4+ T cells in CD28-/- mice compared with wt mice. Taken together, our data show that resistance to T. gondii in the brain is independent of CD28 and suggest a role for CD28 in development of immune-mediated pathology during TE.

BLOCKADE of CD28/B7 and/or CD40/CD40L pathways has been employed with reasonable success to prevent organ allograft rejection.1.:! Additionally, contemporaneous but not discrete use of rhCfLA4-Ig and antiCD40L monoclonal antibody (MAb) has also been shown to prevent chronic rejection.1.3 In the realm of cellular transplantation (Tx), it has been reported that the use of either rhCfLA4-Ig or anti-CD40L MAb alone resulted in prolongation but not indefinite survival of islet allografts.4 ,5 Based on these observations, we hypothesized that combined transient perioperative blockade of both costimulatory pathways would result in indefinite islet allograft survival, thus allowing maintenance of euglycemia in a diabetic recipient without the need for exogenous insulin. This latter tenet was tested in an MHC-incompatible mouse model of islet cell Tx; the outcome of this novel study is presented herein.

Ischemic injury to cadaver organs is a major risk factor for development of chronic organ dysfunction. We have recently shown that the B7 costimulatory pathway plays a critical role in early organ dysfunction developing after renal cold ischemia/reperfusion injury. We extended these observations to investigate the role of this pathway in the development and progression of chronic organ dysfunction following such injury. Uninephrectomized rats which underwent cold ischemia/reperfusion injury developed progressive proteinuria as compared to uninephrectomized controls. Animals treated with CTLA4Ig, which blocks B7 costimulation, starting on the day of injury had significantly better long-term survival and developed significantly less proteinuria than control animals treated with control Ig. RT-PCR analysis of kidney tissue showed significant reduction in expression of activation and inflammatory cytokines, chemoattractants, and growth factors, as compared to controls. Delaying administration of CTLA4Ig for one week, but not four weeks, after injury was still effective in ameliorating development of progressive proteinuria. Interestingly, selective blockade of B7-1 by a mutant form of CTLA4Ig had no effect on early or chronic organ dysfunction. These findings indicate the long-term functional and molecular consequences of experimental cold ischemia/reperfusion injury, and suggest that B7-2 is critical in the development of organ dysfunction following ischemic injury, even in the absence of alloantigen.

Blocking the CD28-B7 T cell costimulatory activation pathway protects animals from developing experimental autoimmune encephalomyelitis (EAE). In the mouse EAE model, selective blockade of B7-1 by specific mAbs has been shown to protect animals from EAE. In the Lewis rat model, we have shown that CD28-B7 blockade by systemic administration of CTLA4Ig prevents actively induced EAE. Since CTLA4Ig binds to both B7-1 and B7-2, we used a mutant form of CTLA4Ig (CTLA4IgY100F) that binds only B7-1, to study the role of B7-1 blockade in this model. Such a reagent avoids the potential of signaling by mAbs. Systemic administration of CTLA4IgY100F in several dosing regimens did not protect from EAE, and in some protocols worsened disease, while CTLA4Ig was always protective. In contrast, systemic injection of APCs preincubated ex vivo with the encephalitogenic peptide of myelin basic protein and either CTLA4Ig or CTLA4IgY100F protected recipients from disease. In vitro studies confirmed the in vivo observations and showed that primed lymph node cells from protected animals had decreased proliferative responses to myelin basic protein as compared with controls, while lymphocytes from animals treated with systemic CTLA4gY100F did not. More importantly, systemic administration of CTLA4IgY100F abrogated the protective effect of ex vivo treated APCs. These data suggest an important regulatory role for B7-1, perhaps through binding to CTLA4, in this model of EAE. Understanding the role and mechanisms of selective blockade of costimulatory molecules has implications for therapy of autoimmune disease.

We used a novel approach to study the role of CD28-B7 T cell costimulatory blockade in experimental autoimmune encephalomyelitis (EAE) in the Lewis rat model. APCs were incubated in vitro with CTLA4Ig and the encephalitogenic peptide p71-90 of myelin basic protein. Systemic injection of APCs treated ex vivo with p71-90 and CTLA4Ig before immunization protected animals from clinical EAE. Systemic injection of APCs treated with CTLA4Ig alone, CTLA4Ig and control peptide, peptide alone, or peptide and control Ig was not protective. Injection of APCs treated ex vivo with CTLA4Ig and p71-90 on the day of immunization was also protective, but delaying the injection till day 7 after immunization impaired the protective effect. Immunohistologically, protected animals had decreased inflammatory responses, with inhibition of Th1 and sparing of Th2 cytokines in the brain. Preincubation of APCs with p71-90 and a mutant form of CTLA4Ig that binds only B7-1 also protected animals from developing EAE. These results suggest that ex vivo blockade of CD28-B7-1 leads to the generation of regulatory cells, presumably Th2, which inhibit the generation or priming of encephalitogenic T cells and suppress the autoimmune response to the specific Ag in vivo. These observations have therapeutic implications for autoimmune diseases and transplantation.

Using a unique loan level data set that links individual household credit ratings with property and loan characteristics, we test the extent to which homeowners' equity and credit ratings affect the likelihood that mortgage loans will be refinanced as interest rates fall. The logit model estimates strongly support the importance of both the equity and credit ratings affect the likelihood that mortgage loans will be refinanced as interest rates fall. The logit model estimates strongly support the importance of both the equity and credit variable. These results are interesting both from the viewpoint of investors in mortgage products (since prepayments are directly affected) and from the perspective of monetary policy (since refinancings are one channel by which lower interest rates normally help reliquify households).

The hyaluronan (HA)-binding function (lectin function) of the leukocyte homing receptor, CD44, is tightly regulated. Herein we address possible mechanisms that regulate CD44 isoform-specific HA binding. Binding studies with melanoma transfectants expressing CD44H, CD44E, or with soluble immunoglobulin fusions of CD44H and CD44E (CD44H-Rg, CD44E-Rg) showed that although both CD44 isoforms can bind HA, CD44H binds HA more efficiently than CD44E. Using CD44-Rg fusion proteins we show that the variably spliced exons in CD44E, V8-V10, specifically reduce the lectin function of CD44, while replacement of V8-V10 by an ICAM-1 immunoglobulin domain restores binding to a level comparable to that of CD44H. Conversely, CD44 bound HA very weakly when exons V8-V10 were replaced with a CD34 mucin domain, which is heavily modified by O-linked glycans. Production of CD44E-Rg or incubation of CD44E-expressing transfectants in the presence of an O-linked glycosylation inhibitor restored HA binding to CD44H-Rg and to cell surface CD44H levels, respectively. We conclude that differential splicing provides a regulatory mechanism for CD44 lectin function and that this effect is due in part to O-linked carbohydrate moieties which are added to the Ser/Thr rich regions encoded by the variably spliced CD44 exons. Alternative splicing resulting in changes in protein glycosylation provide a novel mechanism for the regulation of lectin activity.

CD28 and CTLA-4 are homologous T cell receptors of the immunoglobulin (Ig) superfamily, which bind B7 molecules (CD80 and CD86) on antigen-presenting cells and transmit important costimulatory signals during T cell activation. Here we have investigated the subunit structure of CTLA-4 and the stoichiometry of its binding to B7 molecules. We demonstrate CTLA-4 is a homodimer interconnected by one disulfide bond in the extracellular domain at cysteine residue 120. Each monomeric polypeptide chain of CTLA-4 contains a high affinity binding site for B7 molecules; soluble CTLA-4 and CD86 form complexes containing equimolar amounts of monomeric CTLA-4 and CD86 (i.e. a 2:2 molecular complex). Thus, CTLA-4 and probably CD28 have a receptor structure consisting of preexisting covalent homodimers with two binding sites. Dimerization of CTLA-4 and CD28 is not required for B7 binding, nor is it sufficient to trigger signaling.

Glycosaminoglycan-modified isoforms of CD44 have been implicated in growth factor presentation at sites of inflammation. In the present study we show that COS cell transfectants expressing CD44 isoforms containing the alternatively spliced exon V3 are modified with heparan sulfate (HS). Binding studies with three HS-binding growth factors, basic-fibroblast growth factor (b-FGF), heparin binding-epidermal growth factor (HB-EGF), and amphiregulin, showed that the HS-modified CD44 isoforms are able to bind to b-FGF and HB-EGF, but not AR. b-FGF and HB-EGF binding to HS-modified CD44 was eliminated by pretreating the protein with heparitinase or by blocking with free heparin. HS-modified CD44 immunoprecipitated from keratinocytes, which express a CD44 isoform containing V3, also bound to b-FGF. We examined whether HS-modified CD44 isoforms were expressed by activated endothelial cells where they might present HS-binding growth factors to leukocytes during an inflammatory response. PCR and antibody-binding studies showed that activated cultured endothelial cells only express the CD44H isoform which does not contain any of the variably spliced exons including V3. Immunohistological studies with antibodies directed to CD44 extracellular domains encoded by the variably spliced exons showed that vascular endothelial cells in inflamed skin tissue sections do not express CD44 spliced variants. Keratinocytes, monocytes, and dendritic cells in the same specimens were found to express variably spliced CD44. 35SO4(-2)-labeling experiments demonstrated that activated cultured endothelial cells do not express detectable levels of chondroitin sulfate or HS-modified CD44. Our results suggest that one of the functions of CD44 isoforms expressing V3 is to bind and present a subset of HS-binding proteins. Furthermore, it is probable that HS-modified CD44 is involved in the presentation of HS-binding proteins by keratinocytes in inflamed skin. However, our data suggests that CD44 is not likely to be the proteoglycan principally involved in presenting HS-binding growth factors to leukocytes on the vascular cell wall.

CD44 is a polymorphic glycoprotein expressed on the surface of many tissues and cell lines which has been implicated in a number of cellular functions including lymphocyte homing to mucosal lymphoid tissue (Peyers patches), leukocyte activation, lymphopoiesis, and tumor metastasis. The predominant isoform found on human leukocytes, CD44H, is a receptor for hyaluronic acid. Because of the prominent role CD44 plays in diverse biological processes, we set out to identify the hyaluronic acid binding site(s) in the extracellular domain of CD44H. Using truncation and site-directed mutagenesis we identified two regions containing clusters of conserved basic residues which are important in hyaluronic acid binding. One of these regions is situated near the NH2 terminus and is homologous to other hyaluronic acid binding proteins including cartilage link protein. The other more membrane proximal region lies outside the link protein homologous domain. Mutagenesis of basic residues within these regions established their role as determinants in hyaluronic acid binding. Mutation of Arg 41, a position where a basic residue is conserved in all hyaluronic acid binding proteins, completely abolished binding suggesting that this residue plays a critical role in hyaluronic acid binding.