Bevacizumab suppresses choroidal neovascularisation caused by pathological myopia.
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Adult↗
Biomedical subjects
Q D Nguyen
Publications and source records attributed to Q D Nguyen.
Avalanche behavior in yield stress fluids.
We show that, above a critical stress, typical yield stress fluids (gels and clay suspensions) and soft glassy materials (colloidal glasses) start flowing abruptly and subsequently accelerate, leading to avalanches that are remarkably similar to those of granular materials. Rheometrical tests reveal that this is associated with a bifurcation in rheological behavior: for small stresses, the viscosity increases in time; the material eventually stops flowing. For slightly larger stresses the viscosity decreases continuously in time; the flow accelerates. Thus the viscosity jumps discontinuously to infinity at the critical stress. We propose a simple physical model capable of reproducing these effects.
Journal Article↗
Clinical protocol. An open-label, phase I, single administration, dose-escalation study of ADGVPEDF.11D (ADPEDF) in neovascular age-related macular degeneration (AMD).
Age-Related Macular Degeneration (AMD) is, together with Diabetic Retinopathy, the most common cause of vision loss among adults in the U.S. and other developed countries. In the U.S., at least 1.7 million people have impaired vision due to AMD. Every year, more than 165,000 people contract AMD and 16,000 go blind from it, predominantly from a rapidly progressing form of the disease called "wet" AMD. Wet AMD is characterized by serious or hemorrhagic detachment of the retinal pigment epithelium and choroidal neovascularization. The macula has the highest concentration of photoreceptors facilitating central vision and permitting high-resolution visual acuity. The damage caused by the leakage and fibrovascular scarring in wet AMD leads to profound loss of central vision and severe loss of visual acuity (usually 20/200 or worse). People with wet AMD have several limitations, including inability to read, inability to recognize faces or drive, and the disease often leads to blindness. The onset of severe visual changes in wet AMD can occur suddenly. More than 400,000 Americans are currently affected by this form of the disease, and the incidence is rising rapidly with the aging of the population. Therefore, the serious consequences of this disease along with the limited treatment options and their effectiveness make this a very good candidate for a gene transfer treatment approach. The investigational agent, Ad(GV)PEDF.11D, is an E1-, partial E3-, E4- deleted replication-deficient, adenovirus serotype 5, gene transfer vector. The transgene in this vector is the cDNA for human pigment epithelium-derived factor (PEDF). PEDF is one of the most potent known antiangiogenic proteins found in humans. While Ad(GV)PEDF.11D is able to transduce many somatic cell types, the natural barrier to other tissues created by the retina limits the ability of Ad(GV)PEDF.11D to affect tissues other than in the eye. Intravitreal administration of Ad(GV)PEDF.11D provides a convenient means of delivering PEDF to the relevant cells within the eye likely to result in a more prolonged duration of effect versus administration of the PEDF protein alone. In three murine disease models (the laser-induced choroidal neovascularization model, the VEGF transgenic model, and the retinopathy of prematurity model) significant inhibition of neovascularization (up to 85%) was demonstrated with doses of Ad(GV)PEDF vectors ranging from 1 x 10(8) to 1 x 10(9) pu. In toxicology studies performed in Cynomolgus monkeys, a dose-related inflammatory response was observed. A dose of 1 x 10(8) pu caused no adverse effects, while the inflammatory response observed at 1 x 10(9) pu was minimal and fully reversible. The observed inflammatory response at doses of 1 x 10(10) and 5 x 10(10) pu were increasingly severe. The proposed clinical trial is an open-label, dose-escalation, phase I study to investigate the safety, tolerability and potential activity of intravitreal injection of Ad(GV)PEDF.11D in patients with wet AMD. Ad(GV)PEDF.11D will be injected once via intravitreal injection into the eye with the most advanced AMD based on visual acuity. Subjects will be age 50 or over and have severe wet AMD in at least one eye defined by a best-corrected vision of 20/200 or worse. The primary objectives of this investigation are: (1) to assess the safety, tolerability and feasibility of intravitreal injection of Ad(GV)PEDF.11D in patients with severe, neovascular AMD, (2) to identify the maximum tolerated dose (MTD) of Ad(GV)PEDF.11D, and (3) to get some indication of potential activity of Ad(GV)PEDF.11D.
Adenoviridae↗
Sclerosing inflammatory pseudotumor of the eye.
We report the clinical course and pathologic findings in a case of intraocular sclerosing inflammatory pseudotumor in a 21-year-old man. The patient initially had a unilateral right interstitial keratitis, scleritis, uveitis, ciliary body mass, and retinal detachment. Scleral and vitreous biopsy specimens revealed an inflammatory process. The eye was eventually enucleated despite therapy with high doses of prednisone and ciprofloxacin hydrochloride. Histologic examination of the globe showed nongranulomatous, acute (neutrophils) and chronic (lymphocytes and histiocytes) inflammation with proliferation of fibrous tissue within the vitreous cavity, uvea, sclera, and contiguous orbital fibroadipose tissue. The contralateral eye later developed a similar mass that resolved following aggressive and prolonged immunosuppressive therapy with retention of 20/16 visual acuity.
Adult↗
Amniotic membrane inlay and overlay grafting for corneal epithelial defects and stromal ulcers.
OBJECTIVES: To determine the effect of amniotic membrane transplantation (AMT) on persistent corneal epithelial defects (PEDs) and to compare the efficacy between inlay and overlay techniques. METHODS: Thirty patients (30 eyes) underwent AMT for PED. The use of AMT was restricted to patients in whom all previous measures, including bandage contact lens and tarsorrhaphy, had failed. The amniotic membrane was placed on the surface of the cornea in overlay (group A) or inlay (group B) fashion. RESULTS: The PED healed after the first AMT in 21 eyes (70%) within an average of 25.5 days after surgery and recurred in 6 eyes (29%). Among the 22 eyes treated with an overlay AMT (group A), the PED healed after the first AMT in 14 eyes (64%) within an average of 24.5 days and recurred in 4 eyes (29%). Among the 8 eyes treated with an inlay AMT (group B), the PED healed within an average of 27.4 days after AMT, which did not statistically significantly differ from group A (P = .72). The PED healed after the first AMT in 7 eyes (88%) and recurred in 2 (29%) of 7 eyes. CONCLUSIONS: The AMT can be helpful in the treatment of PED in which all other conventional management has failed. However, the success rate in our study was not as high as that previously reported, and our results showed a high incidence of recurrences of epithelial defects. We did not find any difference between overlay and inlay techniques in terms of healing time and recurrence rate.
Adult↗
Activation of cellular invasion by trefoil peptides and src is mediated by cyclooxygenase- and thromboxane A2 receptor-dependent signaling pathways.
We have investigated the possible functional relationships between cellular invasion pathways induced by trefoil factors (TFFs), src, and the cyclooxygenases COX-1 and COX-2. Pharmacological inhibitors of the Rho small GTPase (C3 exoenzyme), phospholipase C (U-73122), cyclooxygenases (SC-560, NS-398), and the thromboxane A2 receptor (TXA2-R) antagonist SQ-295 completely abolished invasion induced by intestinal trefoil factor, pS2, and src in kidney and colonic epithelial cells MDCKts.src and PCmsrc. In contrast, invasion was induced by the TXA2-R mimetic U-46619, constitutively activated forms of the heterotrimeric G-proteins Galphaq (AGalphaq), Galpha12, Galpha13 (AGalpha12/13), which are signaling elements downstream of TXA2-R. Ectopic overexpression of pS2 cDNA and protein in MDCKts.src-pS2 cells and human colorectal cancer cells HCT8/S11-pS2 initiate distinct invasion signals that are Rho independent and COX and TXA2-R dependent. We detected a marked induction of COX-2 protein and accumulation of the stable PGH2/TXA2 metabolite TXB2 in the conditioned medium from cells transformed by src. This led to activation of the TXA2-R-dependent invasion pathway, which is monitored via a Rho- and Galpha12/Galpha13-independent mechanism using the Galphaq/PKC signaling cascade. These findings identify a new intracrine/paracrine loop that can be monitored by TFFs and src in inflammatory diseases and progression of colorectal cancers.
Cell Line, Transformed↗
Recent advances in retinopathy of prematurity.
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Cost-Benefit Analysis↗
Erosion and intrusion of silicone rubber scleral buckle. Presentation and management.
OBJECTIVE: To describe the clinical presentation and management of erosion and intrusion of silicone rubber implants that are used in scleral buckling procedures for the treatment of retinal detachment. METHODS: The authors identified four patients from their practices during the last 20 years (1978-1998) who had erosion or intrusion of silicone rubber scleral buckles that were used to manage retinal detachment. Approximately 4400 scleral buckling procedures were performed during this period. A retrospective review of the medical records of all patients was performed. Factors that influenced management decisions concerning the intruding buckle are emphasized. RESULTS: All four patients had myopia. The interval between placement of the scleral buckle and development of intrusion ranged from 1 to 20 years. The buckles were intrascleral in three cases and episcleral in one. Recurrent detachment and vitreous hemorrhage were indications for surgical intervention in three cases. After the surgical removal of buckling elements, visual acuity stabilized in all patients and the retina remained attached in all cases. CONCLUSIONS: Erosion and intrusion of scleral buckle are rare complications of scleral buckling procedures. The intruding buckle may be left intact unless there is significant threat to the integrity of ocular structures, recurrent detachment, or hemorrhage. Manipulation of the encircling band or buckle does not necessarily alter the visual acuity or the status of the retina.
Adult↗
Suppression of cellular invasion by activated G-protein subunits Galphao, Galphai1, Galphai2, and Galphai3 and sequestration of Gbetagamma.
It was shown previously that platelet-activating factor receptors (PAF-Rs) inhibit invasiveness of colonic and kidney epithelial cells induced by the src and Met oncogenes via a pertussis toxin-sensitive mechanism. Therefore, Madin-Darby canine kidney (MDCKts.src) cells were stably transfected with constitutively activated forms of Galphao, Galphai1, Galphai2, Galphai3 (AGalphao/i), two Gbetagamma sequestering proteins [C-terminal end of beta-adrenergic receptor kinase (ct-betaARK) and the Galphat subunit of retinal G-protein transducin], and Gbeta1-Ggamma2 subunits alone or in combination. Cellular invasion induced by src, Met, and leptin was abrogated by the AGalphao/i, ct-betaARK, and Galphat-positive clones, but was induced by coexpression of Gbeta1gamma2. In contrast, invasion stimulated by the trefoil factors (TFFs) pS2 and intestinal trefoil factor in MDCKts.src cells or human colonic epithelial cells PCmsrc and HCT8/S11 was insensitive to PAF, AGalphao, AGalphai1, and AGalphai2, but was abolished by AGalphai3 and the protease-activated receptor-1 (PAR-1) agonist thrombin receptor-activating peptide. Depletion of free Gbetagamma heterodimers by ct-betaARK resulted in a remarkable decrease of cellular adhesion and spreading on collagen matrix. Our data demonstrate the following: 1) PAF-Rs impair cellular invasion induced by src, Met, and leptin via the activation of Galphao and Galphai1 to -3; 2) invasion induced by TFFs is selectively inhibited by PAR-1 receptors and Galphai3 activation; and 3) Gbetagamma dimers are required as positive effectors of invasion pathways induced by oncogenes and epigenetic factors. Thus, redistribution of Galphao/Galphai and Gbeta/gamma heterotrimeric G-proteins by PAF-R and PAR-1 exert differential functions on positive and negative signaling pathways involved in cellular invasion and may serve as potential targets for anticancer therapy.
Animals↗
Elevated vitreous concentration of monoclonal immunoglobulin manifesting as schlieren in juvenile rheumatoid arthritis-associated uveitis.
We report the clinical findings and analysis of the immunoglobulin (Ig) composition of the vitreous of a 10-year-old girl with juvenile rheumatoid arthritis-associated uveitis. The vitreous had a schlieren appearance at the time of pars plana lensectomy and vitrectomy. Analysis of the vitreous fluid revealed marked elevation of IgG, IgM, IgA, and albumin levels relative to vitreous fluids from control patients without uveitis. The immunoglobulin coefficients were also elevated for the IgG and IgM classes of immunoglobulins. Immunofixation electrophoresis of the vitreous fluid revealed 2 distinct bands of restricted electrophoretic mobility. These studies suggest that there may be local (intraocular) production of immunoglobulins as an immunologic response in ocular inflammatory diseases such as juvenile rheumatoid arthritis-associated uveitis and that this immunologic response may be monoclonal (possibly biclonal or oligoclonal) in nature.
Aged↗
Effect of Fas and Fas ligand deficiency in resistance of C57BL/6 mice to HSV-1 keratitis and chorioretinitis.
PURPOSE: To investigate the effect of Fas and Fas ligand (FasL) deficiency on the development of herpes stromal keratitis and on the von Szily model of herpes retinitis in C57BL/6 mice, which are ordinarily resistant to development of both of these herpetic diseases. METHODS: Anterior chamber inoculation of the right eye of each mouse with various titers of HSV-1 (KOS strain) was performed. Both eyes of each mouse were enucleated on postinoculation day 15 and processed for histopathologic examination. HSV-1 was inoculated into one cornea of other mice, and the severity of stromal keratitis was scored. RESULTS: Contralateral destructive chorioretinitis developed in susceptible Balb/cByj mice (19/23); ipsilateral chorioretinitis did not occur (0/23). Stromal keratitis developed in susceptible C.AL-20 mice (15/16). None of the C57BL/6 (0/10 for keratitis or 0/20 for retinitis) developed inflammation. Neither did B6.SMN.C3H.gld (FasL deficient; 0/12 or 0/28) or B6.MRL.lpr (Fas deficient; 0/11 or 0/34) mice (keratitis or contralateral chorioretinitis). Minimal scattering of inflammatory cells in the contralateral retina but not destructive chorioretinitis was observed in two C57BL/6, three B6.SMN.C3H.gld, and five B6.MRL.lpr mice. Few inflammatory cells were also found in the ipsilateral vitreous and vitreoretinal interface (but not destructive chorioretinitis) of all C57BL/6, two gld, and three lpr mice. CONCLUSIONS: Immune dysregulation secondary to deficiency in Fas or FasL system does not influence the resistance of the C57BL/6 mice to develop herpes simplex keratitis or destructive herpes simplex chorioretinitis.
Animals↗
Immune recovery uveitis in patients with AIDS and cytomegalovirus retinitis after highly active antiretroviral therapy.
PURPOSE: To estimate the incidence and describe the characteristics of immune recovery uveitis in patients with acquired immunodeficiency syndrome (AIDS) and cytomegalovirus retinitis treated with highly active antiretroviral therapy. METHODS: The records of all patients with AIDS and cytomegalovirus retinitis from 1995 to 1998 seen at the AIDS Ophthalmology Service of the Johns Hopkins Medical Institutions were reviewed. Eighty-two patients with cytomegalovirus retinitis treated with highly active antiretroviral therapy were identified. Thirty-three patients (40.2%) were classified as responders to highly active antiretroviral therapy, defined as an increase in CD4+ T-cell count by 50 cells/microL or more to a level of 100 cells/microL or more. RESULTS: Immune recovery uveitis occurred in six patients. Among the 33 patients with an immunologic response to highly active antiretroviral therapy, the incidence rate of immune recovery uveitis was 0.109/person-year. Ocular complications associated with immune recovery uveitis included cystoid macular edema (four patients), epiretinal membranes (two patients), and optic disk neovascularization (one patient). CONCLUSIONS: Immune recovery uveitis was uncommon in our population but may have vision-impairing complications.
AIDS-Related Opportunistic Infections↗
Choroidopathy of systemic lupus erythematosus.
PURPOSE: To describe the ocular and systemic manifestations associated with systemic lupus erythematosus (SLE) choroidopathy. METHODS: Three new cases of choroidopathy in patients with active SLE were described. Twenty-five published cases of lupus choroidopathy were summarized. RESULTS: There have been 28 cases of lupus choroidopathy (47 involved eyes) that have been reported in the English literature since 1968, including the three current cases. Only two of the patients were male. The choroidopathy was bilateral in 19 patients (68%). All 28 patients (100%) had active systemic vascular disease at the onset of their choroidopathy; 18 (64%) had nephropathy and 10 (36%) had central nervous system (CNS) lupus vasculitis. All but one of the patients had a known diagnosis of SLE at the onset of choroidopathy. 30 of the 47 involved eyes had presenting visual acuity of 20/40 or better; 14 eyes showed improvement in visual acuity with therapy. 23 patients (82%) had resolution of their choroidopathy when their systemic disease was brought under control. Despite treatment, 4 of the 28 patients (14%) died from complications of SLE. CONCLUSIONS: Although less known than retinopathy, lupus choroidopathy may be more common than generally appreciated. It usually serves as a sensitive indicator of lupus activity. The presence of SLE choroidopathy is generally indicative of coexistent (although sometimes occult) nephropathy, CNS vasculitis, and other SLE visceral lesions. Immunomodulation of the systemic disease can lead to improvement and resolution of the systemic vasculitis as well as the choroidopathy.
Adolescent↗
Infectious crystalline keratopathy and endophthalmitis secondary to Mycobacterium abscessus in a monocular patient with Stevens-Johnson syndrome.
PURPOSE: To describe the clinical and laboratory features of infectious crystalline keratopathy and endophthalmitis secondary to Mycobacterium abscessus in a patient with Stevens-Johnson syndrome. METHOD: Case report. A 19-year-old man with a history of Stevens-Johnson syndrome and multiple corneal transplants developed white crystalline corneal infiltrates. RESULTS: Anterior chamber aspirate disclosed acid-fast bacilli. A repeat corneal transplant was performed and antibiotic therapy begun. Histopathology showed focal acute inflammation surrounding collections of acid-fast bacilli, which were speciated as M. abscessus. CONCLUSIONS: M. abscessus is a cause of infectious crystalline keratopathy and endophthalmitis. Risk factors include ocular surface disease, corneal transplantation, and immunosuppressive therapy.
Adult↗
Angiotensinogen T174M and M235T gene polymorphisms are associated with the extent of coronary atherosclerosis.
BACKGROUND: The relations of the angiotensinogen (AGT) T174M and M235T gene polymorphisms to the risk of coronary heart disease (CHD) have been investigated in only a few studies with conflicting results. RESULTS: Therefore, we analysed the relationship of the AGT gene polymorphisms to the presence and extent of CHD in 2250 male Caucasians whose coronary anatomy was defined by means of coronary angiography. The relative frequencies of the T and M alleles of the T174M and of the M235T gene variation did not significantly differ between patients without or with single-, double- or triple-vessel disease and between subjects without or with myocardial infarction (MI). In contrast the mean CHD score--defined by Gensini--was higher within MM homozygotes of the T174M gene variation than within TT genotypes; TM subjects had intermediate values. In M235T genotypes, mean CHD scores were similar in the total sample and in older individuals (> or = 62 years), whereas in younger individuals (< 62 years) a higher CHD score was found within AGT 235 T allele carriers than within MM homozygotes. In younger individuals with high apoAI plasma levels, the mean CHD score was clearly higher within TT homozygotes of the M235T gene variation than within MM genotypes; MT subjects had intermediate values. An interaction between both angiotensinogen gene polymorphisms on the extent of CHD or on the risk of non-fatal MI were not observed when the M allele of AGT T174M was combined either with the T allele or the TT genotype of M235T. CONCLUSIONS: The present study strengthens the hypothesis of an association of both angiotensinogen gene polymorphisms with the extent of coronary heart disease.
Alleles↗
Scleral patch graft in the management of necrotizing scleritis.
NS is a rare but devastating consequence of certain connective tissue disorders, most commonly RA. The presence of NS mandates that patients be treated with at least one immunosuppressive chemotherapeutic drug. The cure rate is high in such instances after 1 year of freedom from any evidence of recurrent inflammation. Surgical treatment through tectonic scleral and peripheral corneal grafting is rarely (although sometimes) indicated, except in instances of NS that has advanced to the point of perforation of the globe. Various graft materials can be used, including fascia lata, periosteum, split-thickness dermis, Gore-Tex (synthetic), aortic tissue, and autologous or homologous sclera. Surgical treatment alone will not solve the problem for the patient. The physician also must control the underlying immunoregulatory dysfunction that has caused the destruction initially to protect the graft and, subsequently, the patient's eye.
Female↗
Saving the vision of children with juvenile rheumatoid arthritis-associated uveitis.
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Adjuvants, Immunologic↗
ACE I/D gene polymorphism: presence of the ACE D allele increases the risk of coronary artery disease in younger individuals.
BACKGROUND: Presence of the D allele or homozygosity for the deletion (D) allele of the ACE insertion/deletion (I/D) polymorphism has been discussed as potent risk factor for coronary artery disease (CAD) and myocardial infarction (MI). METHODS AND RESULTS: In 2267 male Caucasians the relation of the ACE I/D gene polymorphism to CAD and MI were investigated. An association of the D allele to CAD was detected in younger subjects (e.g. < 61.7 years, mean value), but not in older patients (e.g. > or = 61.7 years). Additional exclusion of individuals with other cardiovascular risk factors (e.g. high BMI) produced an even stronger association of the D allele to CAD. In contrast, a relation of this polymorphism to non-fatal MI was only observed in older subjects; additional limitation to individuals without cardiovascular risk factors (e.g. BMI and/or diabetes) yielded a further enhancement of this association to MI. In younger subjects (e.g. < 61.7 years) the gene polymorphism was not related to non-fatal MI even after exclusion of additional risk factors. CONCLUSIONS: The present large case-control study strengthens the assumption of an association of the ACE D allele with the risk of ischemic heart disease.
Adult↗