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101.
Maminishkis A Jalickee S Blaug SA Rymer J Yerxa BR Peterson WM Miller SS 《Investigative ophthalmology & visual science》2002,43(11):3555-3566
PURPOSE: To investigate the effects of INS37217, a synthetic P2Y(2) receptor agonist, on intracellular calcium signaling, electrophysiology, and fluid transport in vitro and on experimentally induced retinal detachment in rat eyes in vivo. METHODS: Freshly isolated monolayers of bovine and human fetal RPE were mounted in Ussing chambers for measurements of cytosolic calcium levels ([Ca(2+)](i)), membrane voltages and resistances, and transepithelial fluid transport. Retinal detachments were experimentally produced in Long-Evans rats by injecting modified phosphate-buffered saline into the subretinal space (SRS). Experimental or vehicle solutions were injected into the vitreous, and the size of blebs in the SRS was scored under masked conditions. RESULTS: Addition of INS37217 to Ringer's solution bathing the apical membrane transiently increased [Ca(2+)](i), altered membrane voltages and resistances and generally produced responses that were similar in magnitude to those of uridine triphosphate (UTP). In fluid transport experiments performed with the capacitance probe technique, INS37217 significantly increased fluid absorption across freshly isolated bovine and fetal human RPE monolayers. All in vitro results were blocked by apical 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid (DIDS), which has been shown to block P2Y(2) receptors in the RPE. Intravitreal administration of INS37217, but not UTP, in the rat model of retinal detachment enhanced the removal of SRS fluid and facilitated retinal reattachment when compared with vehicle control. CONCLUSIONS: These findings indicate that INS37217 stimulates the RPE fluid "pump" function in vitro by activating P2Y(2) receptors at the apical membrane. In vivo INS37217 enhances the rates of subretinal fluid reabsorption in experimentally induced retinal detachments in rats and may be therapeutically useful for treating a variety of retinal diseases that result in fluid accumulation in the subretinal space. 相似文献
102.
Brooks BP Larson DM Chan CC Kjellstrom S Smith RS Crawford MA Lamoreux L Huizing M Hess R Jiao X Hejtmancik JF Maminishkis A John SW Bush R Pavan WJ 《Investigative ophthalmology & visual science》2007,48(9):3905-3913
PURPOSE: To characterize the ocular phenotype resulting from mutation of Rab38, a candidate gene for Hermansky-Pudlak syndrome. METHODS: Chocolate mice (cht, Rab38(cht/cht)) and control heterozygous (Rab38(cht/)(+)) and wild-type mice were examined clinically, histologically, ultrastructurally, and electrophysiologically. Mice homozygous for both the Rab38(cht) and the Tyrp1(b) alleles were similarly examined. RESULTS: Rab38(cht/cht) mice showed variable peripheral iris transillumination defects at 2 months of age. Patches of RPE hypopigmentation were noted clinically in 57% of Rab38(cht/cht) eyes and 6% of Rab38(cht/)(+) eyes. Rab38(cht/cht) mice exhibited thinning of the iris and RPE and larger b-wave amplitudes in the scotopic range when compared with the control animals. Compared with wild-type mice, Rab38(cht/cht) melanosomes were smaller and there were fewer in neuroectodermally derived retinal pigment epithelium; in neural crest-derived choroid melanocytes, they were smaller in size only. Mutation of both Rab38 and Tyrp1 produced mice with ocular and coat color pigment dilution greater than that seen with either mutation alone. Comprehensive clinical and pathologic analyses showed no other organ system or blood defects in Rab38(cht/cht) mice. CONCLUSIONS: Rab38(cht/cht) mice show ocular characteristics reminiscent of human oculocutaneous albinism, as well as iris and RPE thinning. The synergistic effects of the Rab38(cht) and Tyrp1(b) alleles suggest that TYRP1 is not the only target of RAB38 trafficking. This mouse line provides a useful model for studying melanosome biology and its role in human ocular diseases. 相似文献
103.
104.
105.
Arvydas Laurinavicius Benoit Plancoulaine Allan Rasmusson Justinas Besusparis Renaldas Augulis Raimundas Meskauskas Paulette Herlin Aida Laurinaviciene Abir A. Abdelhadi Muftah Islam Miligy Mohammed Aleskandarany Emad A. Rakha Andrew R. Green Ian O. Ellis 《Virchows Archiv : an international journal of pathology》2016,468(4):493-502
106.
Background Context
Although some authors have published case reports describing false negatives in intraoperative neurophysiological monitoring (IONM), a systematic review of causes of false-negative IONM results is lacking.Purpose
The objective of this study was to analyze false-negative IONM findings in spine surgery.Study design
This is a retrospective cohort analysis.Patient sample
A cohort of 109 patients with new postoperative neurologic deficits was analyzed for possible false-negative IONM reporting.Outcome Measures
The causes of false-negative IONM reporting were determined.Materials and Methods
From a cohort of 62,038 monitored spine surgeries, 109 consecutive patients with new postoperative neurologic deficits were reviewed for IONM alarms.Results
Intraoperative neurophysiological monitoring alarms occurred in 87 of 109 surgeries. Nineteen patients with new postoperative neurologic deficits did not have an IONM alarm and surgeons were not warned. In addition, three patients had no interpretable IONM baseline data and no alarms were possible for the duration of the surgery. Therefore, 22 patients were included in the study. The absence of IONM alarms during these 22 surgeries had different origins: “true” false negatives where no waveform changes meeting the alarm criteria occurred despite the appropriate IONM (7); a postoperative development of a deficit (6); failure to monitor the pathway, which became injured (5); the absence of interpretable IONM baseline data which precluded any alarm (3); and technical IONM application issues (1).Conclusions
Overall, the rate of IONM method failing to predict the patient's outcome was very low (0.04%, 22/62,038). Minimizing false negatives requires the application of a proper IONM technique with the limitations of each modality considered in their selection and interpretation. Multimodality IONM provides the most inclusive information, and although it might be impractical to monitor every neural structure that can be at risk, a thorough preoperative consideration of available IONM modalities is important. Delayed development of postoperative deficits cannot be predicted by IONM. Absent baseline IONM data should be treated as an alarm when inconsistent with the patient's preoperative neurologic status. Alarm criteria for IONM may need to be refined for specific procedures and deserves continued study. 相似文献107.
Marzieh Rabiei Arvydas Palevicius Amir Dashti Sohrab Nasiri Ahmad Monshi Akram Doustmohammadi Andrius Vilkauskas Giedrius Janusas 《Materials》2021,14(11)
Taking into account X-ray diffraction, one of the well-known methods for calculating the stress-strain of crystals is Williamson-Hall (W–H). The W-H method has three models, namely (1) Uniform deformation model (UDM); (2) Uniform stress deformation model (USDM); and (3) Uniform deformation energy density model (UDEDM). The USDM and UDEDM models are directly related to the modulus of elasticity (E). Young’s modulus is a key parameter in engineering design and materials development. Young’s modulus is considered in USDM and UDEDM models, but in all previous studies, researchers used the average values of Young’s modulus or they calculated Young’s modulus only for a sharp peak of an XRD pattern or they extracted Young’s modulus from the literature. Therefore, these values are not representative of all peaks derived from X-ray diffraction; as a result, these values are not estimated with high accuracy. Nevertheless, in the current study, the W-H method is used considering the all diffracted planes of the unit cell and super cells (2 × 2 × 2) of Hydroxyapatite (HA), and a new method with the high accuracy of the W-H method in the USDM model is presented to calculate stress (σ) and strain (ε). The accounting for the planar density of atoms is the novelty of this work. Furthermore, the ultrasonic pulse-echo test is performed for the validation of the novelty assumptions. 相似文献
108.
Xueqin Gao Arvydas Usas Ying Tang Aiping Lu Jian Tan Johannes Schneppendahl Adam M. Kozemchak Bing Wang James H. Cummins Rocky S. Tuan Johnny Huard 《Biomaterials》2014
Adult multipotent stem cells have been isolated from a variety of human tissues including human skeletal muscle, which represent an easily accessible source of stem cells. It has been shown that human skeletal muscle-derived stem cells (hMDSCs) are muscle-derived mesenchymal stem cells capable of multipotent differentiation. Although hMDSCs can undergo osteogenic differentiation and form bone when genetically modified to express BMP2; it is still unclear whether hMDSCs are as efficient as human bone marrow mesenchymal stem cells (hBMMSCs) for bone regeneration. The current study aimed to address this question by performing a parallel comparison between hMDSCs and hBMMSCs to evaluate their osteogenic and bone regeneration capacities. Our results demonstrated that hMDSCs and hBMMSCs had similar osteogenic-related gene expression profiles and had similar osteogenic differentiation capacities in vitro when transduced to express BMP2. Both the untransduced hMDSCs and hBMMSCs formed very negligible amounts of bone in the critical sized bone defect model when using a fibrin sealant scaffold; however, when genetically modified with lenti-BMP2, both populations successfully regenerated bone in the defect area. No significant differences were found in the newly formed bone volumes and bone defect coverage between the hMDSC and hBMMSC groups. Although both cell types formed mature bone tissue by 6 weeks post-implantation, the newly formed bone in the hMDSCs group underwent quicker remodelling than the hBMMSCs group. In conclusion, our results demonstrated that hMDSCs are as efficient as hBMMSCs in terms of their bone regeneration capacity; however, both cell types required genetic modification with BMP in order to regenerate bone in vivo. 相似文献
109.
Linas M. Klygis M.D. Rome Jutabha Michael B. McCrohan Arvydas D. Vanagunas 《Abdominal imaging》1993,18(1):10-12
Esophageal perforation is usually an acute, life-threatening event, and its diagnosis can be established on the basis of obvious clinical and radiographic findings. This article describes two cases whereby symptoms of esophageal perforations were masked by concomitant administration of steroids, thus causing marked delay in diagnosis and treatment. Esophageal rupture should be considered when patients receiving steroids develop unexplained fever with pleural effusion or pneumomediastinum, particularly following instrumentation or forceful retching. 相似文献
110.
Synergistic enhancement of bone formation and healing by stem cell-expressed VEGF and bone morphogenetic protein-4 总被引:44,自引:0,他引:44
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Peng H Wright V Usas A Gearhart B Shen HC Cummins J Huard J 《The Journal of clinical investigation》2002,110(6):751-759
We investigated the interaction between angiogenic and osteogenic factors in bone formation and bone healing with ex vivo gene therapy using muscle-derived stem cells genetically engineered to express human bone morphogenetic protein-4 (BMP4), VEGF, or VEGF-specific antagonist (soluble Flt1). Our results show that although VEGF alone did not improve bone regeneration, it acted synergistically with BMP4 to increase recruitment of mesenchymal stem cells, to enhance cell survival, and to augment cartilage formation in the early stages of endochondral bone formation. These early effects, coupled with accelerated cartilage resorption, eventually led to a significant enhancement of bone formation and bone healing. The beneficial effect of VEGF on bone healing elicited by BMP4 depends critically on the ratio of VEGF to BMP4, with an improper ratio leading to detrimental effects on bone healing. Finally, we show that soluble Flt1 inhibits bone formation elicited by BMP4. Thus, VEGF plays an important role in bone formation elicited by BMP4, and it can significantly enhance BMP4-elicited bone formation and regeneration through multiple mechanisms. This study has important implications for the formulation of new strategies to improve bone healing through increasing mesenchymal stem cell recruitment and survival, in combination with muscle-derived stem cell-based gene therapy. 相似文献