Forecasts of tropospheric ozone in the Metropolitan Area of Rio de Janeiro based on missing data imputation and multivariate calibration techniques.

Multivariate calibration based on partial least squares, random forest, and support vector machine methods, combined with the MissForest imputation algorithm, was used to understand the interaction between ozone and nitrogen oxides, carbon monoxide, wind speed, solar radiation, temperature, relative humidity, and others, the data of which were collected by air quality monitoring stations in the metropolitan area of Rio de Janeiro in four distinct sites between, 2014 and, 2018. These techniques provide an easy and feasible way of modeling and analyzing air pollutants and can be used when coupled with other methods. The results showed that random forest and support vector machine chemometric techniques can be used in modeling and predicting tropospheric ozone concentrations, with a coefficient of determination for making predictions up to 0.92, a root-mean square error of calibration between 4.66 and 27.15 µg m-3, and a root-mean square error of prediction between 4.17 and 22.45 µg m-3, depending on the air quality monitoring stations and season.

Vitreous pharmacokinetics and retinal safety of intravitreal preserved versus non-preserved triamcinolone acetonide in rabbit eyes.

PURPOSE: To compare the intravitreal pharmacokinetic profile of a triamcinolone acetonide formulation containing the preservative benzyl alcohol (TA-BA) versus a preservative-free triamcinolone acetonide formulation (TA-PF), and evaluate potential signs of toxicity to the retina. METHODS: A total of 60 New Zealand male white rabbits, divided into two groups, were studied. In the TA-BA group, 30 rabbits received an intravitreal injection of TA-BA (4 mg/0.1 ml) into the right eye. In the TA-PF group, 30 rabbits received an intravitreal injection of TA-PF (4 mg/0.1 ml) into the right eye. The intravitreal drug levels were determined in 25 animals from each group by high-performance liquid chromatography (HPLC). The potential for toxicity associated with the intravitreal triamcinolone injections was evaluated in five randomly selected animals from each group by electroretinography (ERG) and by light microscopy. RESULTS: Median intravitreal concentrations of TA-BA (µg/ml) were 1903.1, 1213.0, 857.8, 442.0, 248.6 at 3, 7, 14, 21 and 28 days after injection. Intravitreal concentrations of TA-PF (µg/ml) were 1032.9, 570.1, 516.6, 347.9, 102.8 at 3, 7, 14, 21 and 28 days after injection. The median intravitreal triamcinolone concentration was significantly higher in the TA-BA compared to the TA-PF group at 7 days post-injection (p < 0.05). There was no significant difference between the two groups in median triamcinolone concentration at the other time points evaluated. There was no evidence of toxic effects on the retina in either group based on ERG or histological analyses. CONCLUSIONS: Following a single intravitreal injection, the median concentration of triamcinolone acetonide is significantly higher in the TA-BA compared to the TA-PF group at 7 days post-injection. No toxic reactions in the retina were observed in either group.

Ocular findings in a patient with Castleman's disease before and after treatment with immunosuppression and plasmapheresis.

A 12-year-old girl with a 3-month history of epistaxis and Castleman's disease presented with blurred vision in both eyes for 2 weeks. Indirect ophthalmoscopy revealed a blurred optic disc margin, venous engorgement and tortuosity, intraretinal hemorrhages and cotton wool spots, and serous detachment of the neurosensory retina in the posterior pole of each eye. Fluorescein angiography and laboratory tests revealed abnormalities consistent with the clinical examination. Six months following institution of immunosuppressive treatment, cryoglobulin levels decreased and visual acuity and funduscopic abnormalities were markedly improved. However, a few microaneurysms, retinal hemorrhages, and venous engorgement and tortuosity persisted. One month after the cessation of immunosuppressive treatment, symptoms related to the hyperviscosity syndrome recurred and the patient was treated with one session of plasmapheresis. One month after the plasmapheresis, the patient's symptoms resolved, laboratory values were normal, visual acuity was 20/15 in both eyes, and the funduscopic examination of each eye was unremarkable.