Improvement of the cell viability of hepatocytes cultured in three-dimensional collagen gels using pump-free perfusion driven by water level difference.

Cell-containing collagen gels are one of the materials employed in tissue engineering and drug testing. A collagen gel is a useful three-dimensional (3D) scaffold that improves various cell functions compared to traditional two-dimensional plastic substrates. However, owing to poor nutrient availability, cells are not viable in thick collagen gels. Perfusion is an effective method for supplying nutrients to the gel. In this study, we maintained hepatocytes embedded in a 3D collagen gel using a simple pump-free perfusion cell culture system with ordinary cell culture products. Flow was generated by the difference in water level in the culture medium. Hepatocytes were found to be viable in a collagen gel of thickness 3.26 (± 0.16 S.E.)-mm for 3 days. In addition, hepatocytes had improved proliferation and gene expression related to liver function in a 3D collagen gel compared to a 2D culture dish. These findings indicate that our perfusion method is useful for investigating the cellular functions of 3D hydrogels.

Efficacies of preoperative prism adaptation test and monocular occlusion for detecting the maximum angle of deviation in intermittent exotropia.

BACKGROUND: The efficacies of prism adaptation test (PAT) and monocular occlusion (MO) and their optimal test durations to detect the maximum angles of deviation at near and distance in eyes with intermittent exotropia (IXT) were assessed and compared. METHODS: We retrospectively reviewed the medical records of 72 patients with IXT. All the patients had undergone the initial strabismus surgery between April 2015 and October 2018 and had been preoperatively tested by both PAT and MO performed on different days for 30 and 60 min. Near and distance deviations after 30 and 60 min of PAT and MO were compared to their baseline measurements obtained immediately after prism wear and before occlusion by alternate prism cover test. The near/distance measurements and required test duration to reveal the maximum deviation angle were also compared between PAT and MO. RESULTS: Compared with the baseline, the near deviation by PAT significantly increased after 30 (P < 0.05) and 60 (P < 0.01) minutes but not the distance deviation. However, the increase after 30 min was not significant. By MO, neither near nor distance deviation showed a significant difference from the baseline after 30 and 60 min. PAT showed a significantly larger near deviation than MO at 30 and 60 min, but a larger distance deviation by PAT was only observed at 30 min. CONCLUSIONS: In patients with basic and convergence insufficiency types of IXT, a 30-minute PAT appears to be more effective than MO in revealing the maximum angle of deviation before strabismus surgery.

UTILITY OF ORAL FLUORESCEIN ANGIOGRAPHY WITH ULTRA-WIDEFIELD IMAGING SYSTEM FOR EVALUATION OF VARIOUS RETINAL DISORDERS.

PURPOSE: To evaluate the utility of oral fluorescein angiography with ultra-widefield imaging system (oral UWF-FA) predominantly in children. METHODS: We recruited 17 patients aged 2 years to 22 years with retinal disorders. Each patient ingested a dose of fluorescein sodium set by body weight mixed with 100 mL of juice. Images were scored using four parameters as follows: branch retinal vessel identification, retinal vessels visualization, foveal avascular zone visualization, and clinically important findings such as leakage, microaneurysms, neovascularization, or significant nonperfusion area visualization. Based on the aggregate score, we classified the image quality into three grades. RESULTS: Sixteen of 17 patients completely ingested the fluorescein sodium, and ultra-widefield fluorescein angiography was performed. Images were classified as high quality in nine cases, moderate quality in four, and poor quality in three. In 13 cases (81.3%), images had adequate quality to evaluate retinal conditions. Of three patients with poor-quality images, 2 took 10 minutes to ingest fluorescein sodium and the other ingested only half the dose. The adverse event of a mild skin rash was noted in one patient. CONCLUSION: Oral ultra-widefield fluorescein angiography is effective in evaluating retinal pathology and is a useful alternative especially for pediatric patients who cannot tolerate intravenous line placement.

Quantification of Eccentric Fixation Using Spectral-Domain Optical Coherence Tomography.

PURPOSE: This study aimed to evaluate the utility of optical coherence tomography (OCT) in the quantification of eccentric fixation in amblyopic patients. MATERIAL AND METHODS: In this study, 14 amblyopic patients and 10 healthy volunteers were enrolled. Under non-mydriatic conditions, fixation tests were performed directly using a fixation ophthalmoscope and indirectly using spectral-domain OCT. For evaluations using OCT, the distance between the fovea and the fixation point, which was determined by a cross-sectional image, was measured. RESULTS: On evaluations of healthy volunteers by OCT, the mean distance between the fixation point and the fovea was 80.4 ± 37.7 µm for the dominant eyes and 63.7 ± 36.4 µm for non-dominant eyes (p = 0.41). In amblyopic patients, on evaluation by OCT, the mean distance between the fixation point and the fovea was 193.8 ± 188.3 µm in amblyopic eyes and 83.5 ± 39.3 µm in paired fellow eyes (p = 0.02). Although OCT could detect eccentric fixation points in all the affected eyes of amblyopic patients, fixation ophthalmoscope was unable to quantify them in 2 of 14 affected eyes. CONCLUSIONS: Compared with a fixation ophthalmoscope, our method using OCT seems to be superior both in quantification and detection of eccentric fixation in amblyopic patients, without the need for mydriasis.