212 research outputs found
Light Transport Refocusing for Unknown Scattering Medium
2014 22nd International Conference on Pattern Recognition,Stockholm, Sweden,24-28 Aug. 2014In this paper we propose a new light transport refocusing method for depth estimation as well as for investigation inside scattering media with unknown scattering properties. Propagated visible light rays through scattering media are utilized in our proposed refocusing method. We use 2D light source to illuminate the scattering media and 2D image sensor for capturing transported rays. The proposed method that uses 4D light transport can clearly visualize shallow depth, as well as deep depth plane of the medium. We apply our light transport refocusing method for depth estimation using conventional depth-from-focus method and for clear visualization by descattering the light rays passing through the medium. To evaluate the effectiveness we have done experiments using acrylic and milk-water type scattering medium in various optical and geometrical conditions. Finally, we show up the results of depth estimation and clear visualization, as well as with numeric evaluation
Cloning and characterization of mr-s, a novel SAM domain protein, predominantly expressed in retinal photoreceptor cells
BACKGROUND: Sterile alpha motif (SAM) domains are ~70 residues long and have been reported as common protein-protein interaction modules. This domain is found in a large number of proteins, including Polycomb group (PcG) proteins and ETS family transcription factors. In this work, we report the cloning and functional characterization of a novel SAM domain-containing protein, which is predominantly expressed in retinal photoreceptors and the pineal gland and is designated mouse mr-s (major retinal SAM domain protein). RESULTS: mr-s is evolutionarily conserved from zebrafish through human, organisms through which the mechanism of photoreceptor development is also highly conserved. Phylogenetic analysis suggests that the SAM domain of mr-s is most closely related to a mouse polyhomeotic (ph) ortholog, Mph1/Rae28, which is known as an epigenetic molecule involved in chromatin modifications. These findings provide the possibility that mr-s may play a critical role by regulating gene expression in photoreceptor development. mr-s is preferentially expressed in the photoreceptors at postnatal day 3–6 (P3-6), when photoreceptors undergo terminal differentiation, and in the adult pineal gland. Transcription of mr-s is directly regulated by the cone-rod homeodomain protein Crx. Immunoprecipitation assay showed that the mr-s protein self-associates mainly through the SAM domain-containing region as well as ph. The mr-s protein localizes mainly in the nucleus, when mr-s is overexpressed in HEK293T cells. Moreover, in the luciferase assays, we found that mr-s protein fused to GAL4 DNA-binding domain functions as a transcriptional repressor. We revealed that the repression activity of mr-s is not due to a homophilic interaction through its SAM domain but to the C-terminal region. CONCLUSION: We identified a novel gene, mr-s, which is predominantly expressed in retinal photoreceptors and pineal gland. Based on its expression pattern and biochemical analysis, we predict that mr-s may function as a transcriptional repressor in photoreceptor cells and in pinealocytes of the pineal gland
Effects of topical latanoprost on optic nerve head circulation in rabbits, monkeys
PURPOSE. To evaluate the effect of topically administrated latanoprost on optic nerve head (ONH) circulation in Dutch rabbits, cynomolgus monkeys, and normal humans. METHODS. The ONH tissue blood velocity (NB ONH ) was determined using the laser speckle method. Latanoprost (0.005%, 30 l) was instilled into one eye, and vehicle into the other eye as a control. In rabbits, NB ONH was measured for 90 minutes after a single instillation and before and after a 7-day once-daily instillation regimen. In monkeys, NB ONH was measured before and after 1, 4, and 7 days of a once-daily instillation regimen. The effect of intravenous indomethacin on the latanoprostinduced NB ONH change was also studied in rabbits and monkeys. In humans, the time-course changes in NB ONH were measured for 4.5 hours before and after a 7-day once-daily instillation regimen. Intraocular pressure (IOP) and systemic parameters were simultaneously studied in each experiment. All measurements were performed by investigators masked to the experimental condition. RESULTS. Latanoprost significantly increased NB ONH 10% to 19% in treated eyes after a single instillation (P ϭ 0.035) or 7-day instillation regimen (P ϭ 0.035) in rabbits, after a 4-day (P ϭ 0.035) or 7-day (P ϭ 0.035) instillation regimen in monkeys, and after a 7-day (P ϭ 0.013) instillation regimen in humans, whereas there were no significant changes in the vehicletreated eyes in any of the experiments (P Ͼ 0.5). Pretreatment with indomethacin (5 mg/kg) abolished the NB ONH increase but not the IOP reduction in latanoprost-treated eyes in rabbits and monkeys. IOP remained unchanged in both eyes in rabbits (P Ͼ 0.4), whereas it significantly decreased only in latanoprost-treated eyes in monkeys (P Ͻ 0.05) and humans (P Ͻ 0.05). CONCLUSIONS. Topical latanoprost significantly increased ONH blood velocity only in treated eyes in rabbits, monkeys, and humans. This effect was independent of the IOP-reducing effect of latanoprost and probably was associated with local penetration of the drug and the production of endogenous prostaglandins. (Invest Ophthalmol Vis Sci. 2001;42:2957-2963 L atanoprost, a recently developed prostaglandin F 2␣ (PGF 2␣ )-related FP receptor agonist compound, 1 is one of the most potent ocular hypotensive eye drops in patients with glaucoma. 2-8 Although intraocular pressure (IOP) is consistently the major risk factor for glaucoma, recent studies indicate that impaired circulation in the optic nerve head (ONH) has a crucial role in glaucomatous optic neuropathy. -11 Previous studies have suggested that topically instilled timolol or betaxolol over a long period can accumulate in the periocular tissues and reach the retrobulbar space in sufficient concentration to have pharmacologic effects on the retrobulbar vessels. 12-14 PGF 2␣ has vasoconstricting or vasodilating effects, depending on its concentration, the nature of the vascular bed, or the animal species. 15-18 Latanoprost also has vasoconstricting effects at higher concentrations 20 Grunwald 21-23 and Gupta et al. In the present study, we examined the effects of not only a single instillation but also a 7-day once-daily instillation regimen of latanoprost on ONH circulation in rabbits, monkeys, and normal humans, by using the noninvasive laser speckle method. MATERIALS AND METHODS Instruments ONH circulation was evaluated using the laser speckle method
Evidence for the Involvement of a Src-Related Tyrosine Kinase inXenopusEgg Activation
AbstractRecently, we have purified a Src-related tyrosine kinase, namedXenopustyrosine kinase (Xyk), from oocytes ofXenopus laevisand found that the enzyme is activated within 1 min following fertilization [Satoet al.(1996)J. Biol. Chem.271, 13250–13257]. A concomitant translocation of a part of the activated enzyme from the membrane fraction to the cytosolic fraction was also observed. In the present study, we show that parthenogenetic egg activation by a synthetic RGDS peptide [Y. Iwao and T. Fujimura, T. (1996)Dev. Biol.177, 558–567], an integrin-interacting peptide, but not by electrical shock or the calcium ionophore A23187 causes the kinase activation, tyrosine phosphorylation, and translocation of Xyk. A synthetic tyrosine kinase-specific inhibitor peptide was employed to analyze the importance of the Xyk activity in egg activation. We found that the peptide inhibits the kinase activity of purified Xyk at IC50of 8 μM. Further, egg activation induced by sperm or RGDS peptide but not by A23187 was inhibited by microinjection of the peptide. In the peptide-microinjected eggs, penetration of the sperm nucleus into the egg cytoplasm and meiotic resumption in the egg were blocked. Indirect immunofluorescence study demonstrates that Xyk is exclusively localized to the cortex ofXenopuseggs, indicating that Xyk can function in close proximity to the sperm–egg or RGDS peptide–egg interaction site. Taken together, these data suggest that the tyrosine kinase Xyk plays an important role in the early events ofXenopusegg activation in a manner independent or upstream of calcium signaling
Prognostic value of an increased in flourine-18 deoxyglucose uptake in patients with myocardial infarction: Comparision with stress thallium imaging
AbstractObjectives. This study was undertaken to evaluate the prognostic value of an increase in fluorine (F)-18 deoxyglucose uptake compared wilh clinical, angiographic and stress thallium findings in patients with myocardial infarction.Background. Positron emission tomography (PET) imaging using F-18 deoxyglucose has been applied to assess tissue viability in patients with coronary artery disease. We hypothesized that patients with a myocardial segment with augmented F-18 deoxyglucose uptake are at high risk for a future cardiac event.Methods. One hundred fifty-eight consecutive patients with myocardial infarction referred for F-18 deoxyglucose PET and stress thallium scans were studied. Follow-up was obtained in 84 patients at a mean interval of 23 months to investigate prognostic implications of radionuclide studies.Results. Seventeen patients had a cardiac event during the follow-up interval. Univariate analysis showed that an increase in F-18 deosyglucose uptake was the best predictor of a future cardiac event (p = 0.0006), followed by the number of stenosed vessels (p = 0.008). In the multivariate analysis, when an increase in F-18 deoxyglucose uptake was entered into the model, only angiographic variables had an independent value, whereas no other radionuclide variables showed value. Among patients who did not show redistribution, a future cardiac event was observed more often in patients with than in those without an increase in F-18 deoxyglucose uptake (p < 0.05).Conclusions. Thus, an increase in F-18 deoxyglucose uptake seemed to be the best predictor of a future cardiac event among all clinical, angiographic and redionuclide variables in this study of stable patients with myocardial infarction. Even when a stress thallium-201 scan does not show redistribution, those patients who have an increase in F-18 deoxyglucose uptake in a PET study may be at risk for a future cardiac event, and these patients may need aggressive treatment to prevent a future cardiac event
Pharmacological Inhibition of Toll-Like Receptor-4 Signaling by TAK242 Prevents and Induces Regression of Experimental Organ Fibrosis
Systemic sclerosis (SSc) is a poorly understood heterogeneous condition with progressive multi-organ fibrosis. Recent genetic and genomic evidence suggest a pathogenic role for dysregulated innate immunity and toll-like receptor (TLR) activity in SSc. Levels of both TLR4, as well as certain endogenous TLR ligands, are elevated in skin and lung tissues from patients with SSc and correlate with clinical disease parameters. Conversely, genetic targeting of TLR4 or its endogenous “damage-associated” ligands ameliorates progressive tissue fibrosis. Targeting TLR4 signaling therefore represents a pharmacological strategy to prevent intractable fibrosis. We examined the effect of TAK242, a small molecule TLR4 inhibitor, in preclinical fibrosis models and in SSc fibroblasts. TAK242 treatment prevented, promoted regression of, bleomycin-induced dermal and pulmonary fibrosis, and reduced the expression of several pro-fibrotic mediators. Furthermore, TAK242 ameliorated peritoneal fibrosis and reduced spontaneous hypodermal thickness in TSK/+ mice. Importantly, TAK242 abrogated collagen synthesis and myofibroblasts differentiation in explanted constitutively active SSc fibroblast. Altogether, these findings identify TAK242 as an anti-fibrotic agent in preclinical models of organ fibrosis. TAK242 might potentially represent a novel strategy for the treatment of SSc and other fibrotic diseases
NO2 sensing properties of macroporous In2O3-based powders fabricated by utilizing ultrasonic spray pyrolysis employing polymethylmethacrylate microspheres as a template
Macroporous (mp-) In2O3-based microspheres as a NO2 sensing material were prepared by the pyrolysis of atomized In(NO3)3 aqueous solutions containing polymethylmethacrylate (PMMA) microspheres (150 nm in diameter) as a template. Well-developed spherical macropores (less than 100 nm in diameter) reflecting the morphology of the PMMA microsphere templates could be formed in the In2O3-based microspheres. The introduction of macropores into In2O3-based microspheres was very effective in improving the NO2 response of their thick films fabricated on an alumina substrate equipped with interdigitated Pt electrodes (gap size: ca. 200 μm) by screen-printing. In addition, the addition of a little amount of SnO2 to the mp-In2O3 microspheres not only lowered the resistance in air but also improved the NO2 response. NO2 sensing properties of non-stacked microspheres of the mp-In2O3 mixed with SnO2 were also investigated by utilizing nano-gap Au electrodes (gap size: ca. 200 nm). The non-stacked microspheres showed fast response and recovery speeds to NO2, because of better diffusion capability of NO2
Importance of pre pump arterial pres sure monitoring in hemodialysis patients
Pre-pump arterial pressure (PreAP) is monitored to avoid generating excessive negative pressure. National Kidney Foundation K/DOQI clinical practice guidelines for vascular access recommend that PreAP should not fall below-250 mmHg because excessive negative PreAP can lead to a decrease in the delivery of blood flow, inadequate dialysis, and hemolysis. Nonetheless, these recommendations are consistently disregarded in clinical practice and pressure sensors are often removed from the dialysis circuit.Thus far,delivered blood flow has been reported to decrease at values more negative than -150 mmHg of PreAP. These values have been analyzed by an ultrasonic flowmeter and not directly measured. Furthermore, no known group has evaluated whether PreAP-induced hemolysis occurs at a particular threshold. Therefore, the aim of this study was to clarify the importance of PreAP in the prediction of inadequate dialysis and hemolysis. By using different diameter needles, human blood samples from healthy volunteers were circulated in a closed dialysis circuit. The relationship between PreAP and delivered blood flow or PreAP and hemolysis was investigated. We also investigated the optimal value for PreAP using several empirical monitoring methods, such as a pressure pillow. Our investigation indicated that PreAP is a critical factor in the determination of delivered blood flow and hemolysis,both of which occured at pressure values more negative than -150 mmHg. With the exception of direct pressure monitoring, commonly used monitoring methods for PreAP were determined to be ineffective. We propose that the use of a vacuum monitor would permit regular measurement of PreAP
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