471 research outputs found
C57BL/6J, DBA/2J, and DBA/2J.Gpnmb+ mice have different visual signal processing in the inner retina
To characterize differences in retinal ganglion cell (RGC) function in mouse strains relevant to disease models. C57BL/6J (B6) and DBA/2J (D2) are the two most common mouse strains; D2 has two mutated genes, tyrosinase-related protein 1 (Tyrp1) and glycoprotein non-metastatic melanoma protein B (Gpnmb), causing iris disease and intraocular pressure (IOP) elevation after 6 months of age that results in RGC degeneration, and is the most widely used model of glaucoma. DBA/2J.Gpnmb(+) (D2.Gpnmb(+)) is the wild type for the Gpnmb mutation and does not develop IOP elevation and glaucoma.
Young (2-4 months of age) B6, D2, and D2.Gpnmb(+) mice (n=6 for each group) were tested with pattern electroretinogram (PERG) in response to different contrasts and spatial frequencies. PERG amplitude and latency dependencies on stimulus parameters (transfer functions) were established for each mouse strain, together with corresponding thresholds for contrast and spatial resolution.
PERG analysis showed that B6, D2, and D2.Gpnmb(+) mice had comparable contrast threshold and spatial resolution. Suprathreshold spatial contrast processing, however, had different characteristics in the three strains. PERG amplitude and latency changes with increasing contrast were different between B6 and D2 as well as between D2 and D2.Gpnmb(+).
B6, D2, and D2.Gpnmb(+) mice have different characteristics of PERG spatial contrast processing consistent with different mechanisms of contrast gain control. This may imply differences in the activity of underlying PERG generators and synaptic circuitry in the inner retina
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Long-Term Incidence And Timing Of Intraocular Hypertension After Intravitreal Triamcinolone Acetonide Injection
Purpose: To describe the long-term incidence and timing of steroid-induced ocular hypertension after intravitreal triamcinolone acetonide (IVTA) therapy. Design: Retrospective case series of 929 eyes of 841 patients. Participants: Patients with a variety of posterior segment disorders in a single group practice. Intervention: Pars plana injection of IVTA. Main Outcome Measures: Intraocular pressure (IOP) and requirement for glaucoma surgery. Results: Overall, 929 eyes received ≥1 injections (mean, 1.6) of 4 mg of IVTA. During a mean follow-up period of 14±6.9 months, the Kaplan-Meier cumulative incidences of IOP elevations \u3e21 mmHg at 6, 12, 18, and 24 months post-injection were 28.2%, 34.6%, 41.2%, and 44.6%, respectively; similarly, the incidences of eyes with IOP measurements \u3e25 mmHg were 14.6%, 19.1%, 24.1%, and 28.2%, respectively. At the same time points, lOP-lowering medications were required byl3.0%, 16.9%, 20.7%, and 24.2% of eyes, respectively. Only 3 eyes (0.3%) required lOP-lowering surgery. Preexisting glaucoma, younger age, and a history of an IOP elevation after a previous IVTA injection were risk factors for IOP elevations after IVTA injection. The minimum and maximum follow-up were 3 weeks and 37 months. The mean rate of attrition in this study was 3% per month. Conclusions: Elevations in IOP after IVTA injection are common. Younger patients and eyes with preexisting glaucoma or a history of a steroid response should be monitored more closely for IOP elevations after IVTA therapy
Combining Information from Two Surveys to Estimate County-Level Prevalence Rates of Cancer Risk Factors and Screening
Cancer surveillance requires estimates of the prevalence of cancer risk factors and screening for small areas such as counties. Two popular data sources are the Behavioral Risk Factor Surveillance System (BRFSS), a telephone survey conducted by state agencies, and the National Health Interview Survey (NHIS), an area probability sample survey conducted through face-to-face interviews. Both data sources have advantages and disadvantages. The BRFSS is a larger survey, and almost every county is included in the survey; but it has lower response rates as is typical with telephone surveys, and it does not include subjects who live in households with no telephones. On the other hand, the NHIS is a smaller survey, with the majority of counties not included; but it includes both telephone and non-telephone households and has higher response rates. A preliminary analysis shows that the distributions of cancer screening and risk factors are different for telephone and non-telephone households. Thus, information from the two surveys may be combined to address both nonresponse and noncoverage errors. A hierarchical Bayesian approach that combines information from both surveys is used to construct county-level estimates. The proposed model incorporates potential noncoverage and nonresponse biases in the BRFSS as well as complex sample design features of both surveys. A Markov Chain Monte Carlo method is used to simulate draws from the joint posterior distribution of unknown quantities in the model based on the design-based direct estimates and county-level covariates. Yearly prevalence estimates at the county level for 49 states, as well as for the entire state of Alaska and the District of Columbia, are developed for six outcomes using BRFSS and NHIS data from the years 1997-2000. The outcomes include smoking and use of common cancer screening procedures. The NHIS/BRFSS combined county-level estimates are substantially different from those based on BRFSS alone
Postoperative Complications in the Ahmed Baerveldt Comparison Study During Five Years of Follow-up
To compare the late complications in the Ahmed Baerveldt Comparison Study during 5 years of follow-up
Longitudinal changes in peripapillary atrophy in the ocular hypertension treatment study: A case-control assessment
To explore the association between peripapillary atrophy (PPA) area and conversion from ocular hypertension (OHT) to glaucoma
The impact of overdiagnosis on the selection of efficient lung cancer screening strategies
Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/136362/1/ijc30602_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/136362/2/ijc30602.pd
Three-year Treatment Outcomes in the Ahmed Baerveldt Comparison Study
To compare three year outcomes and complications of the Ahmed FP7 Glaucoma Valve (AGV) and Baerveldt 101–350 Glaucoma Implant (BGI) for the treatment of refractory glaucoma
Five-Year Treatment Outcomes in the Ahmed Baerveldt Comparison Study
To compare the five year outcomes of the Ahmed FP7 Glaucoma Valve (AGV) and the Baerveldt 101-350 Glaucoma Implant (BGI) for the treatment of refractory glaucoma
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