Development of an analytical method to determine methyl alcohol and isopropyl alcohol in food using static headspace gas chromatography.

A method to determine methanol (MeOH) and isopropyl alcohol (IPA) was developed using static headspace sampling (HSS) with gas chromatography (GC) and gas chromatography/mass spectrometry (GC/MS). The optimized HSS-GC and HSS-GC/MS methods were validated according to the parameters. The limit of quantification (LOQ) values for MeOH analyzed by HSS-GC/MS and HSS-GC were 0.50-0.56 and 1.97 mg/L, and the corresponding values for IPA were 0.14-0.21 and 1.51 mg/L, respectively. Recoveries were determined by spiking sample matrices, such as vinegar and tea. MeOH and IPA showed excellent recoveries of 93.80-107.60% and 93.92-104.32% with corresponding precisions of 0.51-7.38% and 0.90-7.70%, respectively. Compared to solid-phase microextraction-GC/MS and HSS-GC, the HSS-GC/MS method showed outstanding values for limit of detection and LOQ with improved precision and accuracy. This HSS-GC/MS method was successfully used to monitor residual solvents in 100 food and functional food products.

Comparison of intraocular pressure fluctuation and glaucoma progression rate between phakic and pseudophakic eyes in pseudoexfoliation glaucoma.

The management of patients with concurrent pseudoexfoliation glaucoma (PXG) and cataract is challenging given its worse prognosis compared to other glaucoma types and the increased risk associated with cataract surgery. In this retrospective study, we investigated the long-term outcomes of cataract surgery in patients with PXG. We enrolled patients with PXG who had undergone cataract surgery at least 2 years previously and compared them with mean deviation (MD) matched patients with phakic eyes. The results showed that both groups experienced a decrease in MD, with the group of pseudophakic eyes exhibiting a significantly higher rate of decline (-2.15 ± 2.66 dB/year vs. -0.86 ± 0.95 dB/year; P = 0.040). Similarly, there was a trend towards more rapid thinning of the retinal nerve fiber layer in the pseudophakic group (-2.92 ± 2.34 µm/year vs. -1.79 ± 1.71 µm/year; P = 0.074). No significant differences in the intraocular pressure parameters were observed between the two groups. Multivariate analysis revealed that pseudophakic lens status was significantly associated with a faster rate of MD decline in patients with PXG (regression coefficient, -1.391; P = 0.022). These findings underscore the importance of close monitoring of patients with pseudophakic PXG to effectively manage glaucoma progression.

Longitudinal Changes in Peripapillary and Macular Vessel Densities in Glaucomatous Eyes With a Single-Hemifield Retinal Nerve Fiber Layer Defect.

PRCIS: The peripapillary vessel density decreased significantly in the affected hemiretina compared with that in the intact hemiretina in glaucomatous eyes with a single-hemifield retinal nerve fiber layer defect. PURPOSE: To evaluate the difference in the change rates of peripapillary vessel density (pVD) and macular vessel density (mVD) measured using optical coherence tomography angiography (OCTA) in glaucomatous eyes with a single-hemifield retinal nerve fiber layer (RNFL) defect. MATERIALS AND METHODS: We performed a retrospective, longitudinal study of 25 patients with glaucoma who were followed up for at least 3 years, with a minimum of 4 visits after baseline OCTA. At each visit, all participants underwent OCTA examination, and the pVD, mVD were measured by removing the large vessels. Changes in the pVD, mVD, peripapillary RNFL thickness (pRNFLT), and macular ganglion cell inner plexiform layer thickness were investigated in the affected and intact hemispheres, and the differences between the 2 hemispheres were compared. RESULTS: In the affected hemiretina, the pVD, mVD, pRNFLT, and mCGIPLT were reduced than that in the intact hemiretina (all, P < 0.001). The changes in pVD and mVD were statistically significant at the 2-year and 3-year follow-ups in the affected hemifield (all, P <0.05). However, pVD and mVD did not show statistically significant changes in the intact hemiretina throughout the follow-up visits. Although the pRNFLT decreased significantly at the 3-year follow-up, the macular ganglion cell inner plexiform layer thickness showed no statistical change at any follow-up visit. Compared with the intact hemisphere, pVD was the only parameter that showed significant changes throughout the follow-up period. CONCLUSION: Although pVD and mVD decreased in the affected hemiretina, the reduction in pVD was significant compared with that in the intact hemiretina.

Evaluation of polycyclic aromatic hydrocarbons content of herbal medicine products in Korea by HPLC-FLD.

The objective of this study was to quantify four polycyclic aromatic hydrocarbons (PAH4) in herbal medicine products in Korea. The PAH4 (benzo[a]anthracene, benzo[b]fluoranthene, chrysene, and benzo[a]pyrene) were analyzed in 70 popularly used herbal medicine products without containing essential oil and containing essential oil matrices, using 3-methylcholanthrene as the internal standard. Ultrasonication and liquid-liquid extraction were followed by HPLC-FLD analysis. Satisfactory linearity (R 2 = 0.99), limit of detection (0.05-0.18 µg/kg), limit of quantification (0.14-0.54 µg/kg), recovery (85.72-112.18%), and precision (0.22-2.90%) of PAH4 were acquired. PAH contamination was detected in all herbal medicine products without containing essential oil and containing essential oil matrices types. In 44 samples of herbal medicine products, all PAH4 were detected, and in two samples of the other herbal medicine products, only benzo[b]fluoranthene was detected. The average concentration of PAH4 was 3.88 µg/kg. The validated analytical method was used for preventing human health risks related to the consumption of herbal medicines.

Validation of analytical methods for acrylic acid from various food products.

Acrylic acid (AA) chemical that endangers human health through contamination of water, soil, and foods. In this study, the extraction, purification, and detection of AA in various food products were established. The contamination level of AA in food products was investigated as well. Food matrices that were used for method validation were crop, fruit, vegetable, seaweed, beverage, sauce, paste, and pickled food, where the validation was confirmed through cross-checking between two different laboratories by checking the accuracy and precision. Furthermore, sample volume for analysis was optimized. Sonication and syringe filtering were all steps preparing headspace analyzer (HA) before GC-MS analysis. Linearity (R2), limit of detection (LOD), limit of quantitation (LOQ), accuracy and precision of AA, were > 0.99, 0.06-0.17 mg/L, 0.18-0.52 mg/L, 90.97-111.93% and 0.12-9.61 RSD% of intra, inter-day, respectively. White rice sample was the only one sample where AA detected (6.19 mg/L) among 102 food samples. Supplementary Information: The online version contains supplementary material available at 10.1007/s10068-022-01131-x.

Risk Assessment and Evaluation of Analytical Method of Polycyclic Aromatic Hydrocarbons (PAHs) for Deep-Fat Fried Pork Products in Korea.

Polycyclic aromatic hydrocarbons (PAHs) are produced during incomplete combustion of organic matter. Many of them are likely to be carcinogenic and cause mutations. In this study, the PAH4 (benzo[a]pyrene (BaP), benz[a]anthracene (BaA), chrysene (CHR), benzo[b]fluoranthene (BbF)) content in deep-fat fried pork was evaluated according to temperature and time, and a risk assessment was conducted. The high performance liquid chromatography-fluorescence detection (HPLC-FLD) method for PAH4 analysis was validated by determining linearity (R2), recovery, limit of detection (LOD), and limit of quantitation (LOQ). The linearity was R2 ≥ 0.99. The PAH4 level was dependent on the temperature, time, and nature of the edible oil. Before heat treatment, the PAH4 content of pork was 0.38 µg/kg. The PAH4 content of deep-fat fried pork ranged from 0.86 to 6.86 µg/kg according to temperature (160, 180, 200 °C) and time (3, 6, 9 min). Exposure to PAH4 via the consumption of deep-fat fried pork for different age groups among the Korean population was 0.01-0.89 µg-TEQBaP/kg/day, with the margin of exposure calculated as 7.88 × 104-5.22 × 106. The PAH4 content and risk of exposure increased proportionally with the heat treatment temperature and time. The survey provided important information in terms of evaluating the health risks that PAH compounds can cause in people's diets due to the heat treatment of pork.

Vision-Threatening Ocular Adverse Events after Vaccination against Coronavirus Disease 2019.

A single-center retrospective observational case series was conducted. This case series enrolled patients who showed ophthalmic manifestations within one week after COVID-19 vaccination at Korea University Guro Hospital in Seoul, Korea, from May 2021 to January 2022. The medical records of patients who complained of ocular symptoms and showed ophthalmic adverse events within one week after COVID-19 vaccination were reviewed. Seventeen eyes from 16 patients with a mean age of 63.8 (range 33-83) years were included in the case series, and all symptoms developed within 1-7 days following inoculation. Retinal vein occlusion in nine eyes (52.9%), retinal artery occlusion in one eye (5.9%), newly developed anterior uveitis in one eye (5.9%), exacerbation of previously diagnosed panuveitis in two eyes (11.8%), and angle-closure attack with high intraocular pressure in four eyes (23.5%) were included. Twelve patients (75%) had been vaccinated with the AstraZeneca (AZD1222) and four (25%) with the Pfizer (BNT162b2) vaccines. Of these, 10 patients (62.5%) experienced ocular disease exacerbation after the first dose, 4 (25%) after the second dose, and 2 (12.5%) after the third dose (booster shot). Eleven patients (64.7%) underwent tests for hematological abnormalities, and three of them tested positive for anti-PF4 antibodies, but no abnormal findings were noted. A causal relationship between vaccination and the ocular manifestations could not be determined, which is a limitation of this study. However, clinicians should consider the effect of COVID-19 vaccination on ophthalmic disease. Further studies are required to elucidate the possible effects of COVID-19 vaccination on the eye.

Comparison of Vision-related Quality of Life Between Normal Tension Glaucoma and Primary Open-angle Glaucoma.

PRCIS: Although there was little difference in overall vision-related quality of life (VRQOL) between patients with normal tension glaucoma (NTG) and primary open-angle glaucoma (POAG) after controlling for confounding factors, POAG tended to have poorer VRQOL, especially in social functioning and dependency, than NTG. PURPOSE: The fundamental goal of treatment of patients with glaucoma is to preserve their VRQOL. The aim of this study was to compare VRQOL between patients with NTG and those with POAG. MATERIALS AND METHODS: The self-reported National Eye Institute Visual Function Questionnaire (NEI VFQ-25) survey was performed, including clinical, demographic, and socioeconomic data from 506 Korean patients with NTG and 287 with POAG. The mean deviation of the integrated binocular visual field was calculated using the best location method. The NEI VFQ-25 results were evaluated by Rasch analysis to control item difficulty and variation in individual response ability. Propensity score matching was used to control for various confounding factors affecting VRQOL. RESULTS: Although patients with POAG tended to have worse VRQOL than those with NTG, there was no statistically significant between-group difference in ocular pain, near and distance activities, mental health, role difficulties, ability to drive, and the overall composite score. However, the social functioning (P=0.016) and dependency (P=0.026) were significantly poorer in POAG patients. CONCLUSIONS: Overall VRQOL in patients with NTG and POAG was found to be similar. However, social functioning and dependency were significantly worse in those with POAG. These findings are relevant to supporting glaucoma patients.

Evaluation of a GC-MS method for benzyl chloride content in processed food, meats, and marine products distributed in Korea.

Benzyl chloride is a harmful chemical that contaminates air, water, and food. A static headspace GC-MS method for determining benzyl chloride in food was developed and validated. Two food matrices (fat/oil and chicken) were used for method validation. Sample preparation involved ultrasonication extraction and purification (syringe filtration). Linearity (R 2) was > 0.99, accuracy ranged from 86.91% to 110%, the limit of detection was 0.04-0.17 mg/kg, and the limit of quantification was 0.13-0.52 mg/kg. Recovery varied from 88.19% to 111.77%, and precision ranged from 0.10% to 1.17% in intraday and interday analyses. Among 102 food items (oils, fats, meat, marine, and egg products) distributed in Korea, benzyl chloride was only detected in six of the marine products. The validated analytical method can be used for routine monitoring of benzyl chloride residues in food and thereby prevent the human health risks associated with the consumption of food contaminated with this chemical.

Development of freshness indicator for monitoring chicken breast quality and freshness during storage.

An indicator for freshness and quality measurement was utilized to perceive changes in freshness quality while storing chicken breasts. Visible color changes of the indicator shows spoilage and freshness of the packaged products. In addition, changes in pH, volatile basic nitrogen (VBN), and Pseudomonas spp. were monitored. The color change sensor (ΔE) reflected the headspace pH during the chicken breasts' packaging process. After storing chicken breast at 20 °C for 24 h, the color change (ΔE) of the indicator for freshness and quality measurement changed. The color change (ΔE) values were correlated with quality characteristics such as sensory, microbiological, and chemical properties that were popularly used to settle the freshness of chicken breast. In conclusion, the results showed that the indicator for freshness and quality measurement was useful in settling the shelf life of chicken breast products by physicochemical changes and monitoring microbial safety. Supplementary Information: The online version contains supplementary material available at 10.1007/s10068-022-01034-x.

Risk Assessment and Determination of Heavy Metals in Home Meal Replacement Products by Using Inductively Coupled Plasma Mass Spectrometry and Direct Mercury Analyzer.

This study quantified six heavy metals (Pb, Cd, As, Sn, Hg, and Me-Hg) in home meal replacement products. Satisfactory linearity (R2 > 0.99), recovery (80.65-118.02%), limits of detection (0.02-2.81 µg/kg), limits of quantification (0.05-8.51 µg/kg), accuracy (80.49-119.87%), precision (0.26-14.93%), standard uncertainty (0.082-0.321%) and relative standard uncertainty (0.084-0.320%) of the six heavy metals were obtained. The average concentration of the six heavy metals was 8.87 µg/kg. Heavy metal concentrations were converted to food intake data of 0.009 µg/kg to recalculate the 95th percentile food intake data (g/day) of individual heavy metals. These were then divided by age group to evaluate the average exposure to heavy metals and determine the 95th percentile of exposure from daily intake and for the whole population, of home meal replacement products. The chronic daily intake amount of six heavy metals was 1.60 × 10-2 µg/kg/day. Based on total chronic daily intake values, the risk and margin of exposure of each of the heavy metals was 9.13 × 107, demonstrating that intake associated with home meal replacement products is negligible.

Bleb-related Porcine Lymphatic Outflow is Greater from Subconjunctival compared to Subtenon Blebs.

Aim: Understanding the mechanism of fluid outflow by comparing the subconjunctival and subtenon spaces can lead to improved ocular therapeutics. The purpose of the current study is to evaluate subconjunctival vs subtenon lymphatic outflow by creating tracer-filled blebs in each location. Methods: Porcine (n = 20) eyes received subconjunctival or subtenon injection(s) of fixable and fluorescent dextrans. Blebs were angiographically imaged using a Heidelberg Spectralis ([Heidelberg Retina Angiograph] HRA + OCT; Heidelberg Engineering) and bleb-related lymphatic outflow pathways were counted. Optical coherence tomography (OCT) imaging of these pathways was used to assess structural lumens and the presence of valve-like structures. Furthermore, a comparison between tracer injection locations (superior/inferior/temporal/nasal) was made. Histologic analyses for subconjunctival and subtenon outflow pathways were performed, to confirm tracer co-localization with molecular lymphatic markers. Results: Subconjunctival blebs demonstrated a greater number of lymphatic outflow pathways compared to subtenon blebs in every quadrant [superior: 6.10 ± 1.18 (subconjunctival) vs 0.50 ± 0.27 (subtenon); temporal: 2.30 ± 0.40 vs 0.10 ± 0.10; nasal: 5.30 ± 0.60 vs 0.30 ± 0.21; inferior: 6.00 ±1.29 vs 0.1 ± 0.1; all comparisons p < 0.001]. For subconjunctival blebs, the temporal quadrant showed fewer lymphatic outflow pathways compared to the nasal side (p = 0.005). Discussion: Subconjunctival blebs accessed greater lymphatic outflow compared to subtenon blebs. Furthermore, regional differences existed, with fewer lymphatic vessels temporal than at the other locations. Clinical significance: Aqueous humor drainage after glaucoma surgery is incompletely understood. The present manuscript adds to our understanding of how lymphatics might influence filtration bleb function. How to cite this article: Lee JY, Strohmaier CA, Akiyama G, et al. Bleb-related Porcine Lymphatic Outflow Is Greater from Subconjunctival compared to Subtenon Blebs. J Curr Glaucoma Pract 2022;16(3):144-151.

Determination of volatile organic compounds (VOCs) levels from various smoking cessation aids by using gas chromatography-mass spectrometry methodology.

An analytical method was validated and developed to determine the levels of volatile organic compounds (VOCs) including 1,3-butadiene, isoprene, acrylonitrile, benzene, toluene, and styrene from smoking cessation aids using by gas chromatography-mass spectrometry (GC-MS). Seventeen non-ignitable cigarette type of smoking cessation aids, liquid-phase of smoking cessation aids, gas-phase of smoking cessation aids, and ignitable cigarette type of smoking cessation aids were analyzed for levels of six VOCs. The proposed method for six VOCs was validated in satisfactory linearity (R2 > 0.99), recovery (80.38-119.14%). limit of detection (LOD) (0.05-0.19 µg/ml), limit of quantification (LOQ) (0.07-0.18 µg/ml), accuracy (80.47-117.28%), and precision (0.15-7.22%). The mean concentrations of six VOCs were generated in 1,3-butadiene (6.18 µg/cigarette), isoprene (0.34 µg/cigarette), acrylonitrile (0.003 µg/cigarette), benzene (ND = not detected, the lower limit of detection), toluene (0.27 µg/cigarette), styrene (0.13 µg/cigarette). Results showed low levels of VOCs from smoking cessation aid except from liquid-phase of smoking cessation aids. These results are necessary to investigate unintentional hazardous substances generated from smoking cessation aids, and develop accurate analytical method in order to obtain scientific basis for safety management.

Analysis of Microvasculature in Nonhuman Primate Macula With Acute Elevated Intraocular Pressure Using Optical Coherence Tomography Angiography.

Purpose: To investigate responses of macular capillary vessel area density (VAD) of superficial and deep retinal vascular plexuses to elevations in intraocular pressure (IOP) in cynomolgus macaque monkeys using optical coherence tomography angiography (OCTA). Methods: In five general anesthetized male cynomolgus monkeys, the IOP was increased incrementally by 10 mmHg from baseline (10 mmHg) to 70 mmHg and then decreased back to 10 mmHg (recovery state). Structural OCT (30° × 30°) and OCTA (20° × 15°) centered on the macula were obtained at each IOP and 3, 15, and 30 minutes after recovery. En face images of the superficial vascular complex (SVC) and deep vascular complex (DVC) were extracted, and VAD (%) compared with that at baseline was calculated. Results: The VADs in the SVC and DVC at baseline and at 30 mmHg IOP were 34.96%, 34.15%, 35.38%, and 30.12%, respectively. The VAD plateaued until 30 mmHg; however, the VAD was affected more in the DVC than in the SVC (P = 0.008) at 30 mmHg. It showed a significant reduction at 40 mmHg (16.52% SVC, P = 0.006; 18.59% DVC, P = 0.012). In the recovery state, the SVC showed full retention of baseline VAD, but the DVC maintained VAD approximately 70% of that at baseline. Structural OCT showed hyperreflectivity in the nuclear layer, retinal swelling, and an undifferentiated ellipsoid zone from 50 mmHg. Conclusions: Despite physiological autoregulation, perifoveal microcirculation was affected at high IOP ≥ 40 mmHg, especially in the DVC, which explains the pathological mechanism of macular vulnerability in ischemic diseases.

Changes After a Month Following Micropulse Cyclophotocoagulation in Normal Porcine Eyes.

Purpose: To analyze the effects on the uvea, including the pars plicata and ciliary muscle, and retina in normal porcine eyes after performing micropulse transslceral cyclophotocoagulation (MP-TSCPC) with the different energy levels, and conventional continuous wave transslceral cyclophotocoagulation. Methods: MP-TSCPC was performed in a total of 15 eyes at the different energy levels of 60 J, 120 J, 180 J, 240 J, and 300 J, respectively. Continuous wave transslceral cyclophotocoagulation was performed in three eyes and the other three eyes were controls. The eyes were enucleated after a month following the laser treatment and the uvea and retina were analyzed using hematoxylin and eosin staining and immunohistochemistry staining. Results: After MP-TSCPC 60 J, the expression of α-smooth muscle actin (α-SMA) and glial fibrillary acidic protein in the ciliary muscle was increased, although there was no structural change in pars plicata. After MP-TSCPC 120 J, partial destruction of the ciliary epithelium was observed in pars plicata, and the retinal thickness was increased. After MP-TSCPC 240 J and 300 J, the structural destruction of the pars plicata and ciliary muscle was observed, and the expression of α-SMA and glial fibrillary acidic protein in pars plicata and the expression of α-SMA in ciliary muscle were increased. Conclusions: Histologic changes in the uvea and peripheral retina were different based on the energy levels of MP-TSCPC. In particular, MP-TSCPC with low energy levels mainly affected the ciliary muscle, while MP-TSCPC with high energy levels affected both the ciliary muscle and pars plicata. Our results may imply a possibility of intraocular damage with MP-TSCPC in humans. Translational Relevance: Based on our research, it is possible to infer the possibility of intraocular damage in humans according to the different levels of energy in the clinic.

Polycyclic Aromatic Hydrocarbon Risk Assessment and Analytical Methods Using QuEchERS Pretreatment for the Evaluation of Herbal Medicine Ingredients in Korea.

Polycyclic aromatic hydrocarbons (PAHs) are carcinogenic and mutagenic compounds that are often formed during the thermal processing of herbal medicine ingredients. In this study, the concentrations of four PAHs (PAH4) in various herbal medicine ingredients were monitored. Further, the QuEChERS method was used to replace conventional pretreatment, a more complex and cumbersome approach. The recovery range of the QuEChERS method ranged between 89.65-118.59%, and the average detection levels of benzo[a]anthracene (BaA), chrysene (CHR), benzo[b]fluoranthene (BbF), and Benzo[a]pyrene (BaP) in 50 herbal medicine ingredients were 0.18, 0.27, 1.13, and 0.17 µg/kg, respectively. The BaP and PAH4 levels in all tested samples were deemed safe according to risk characterization analyses based on European Union and Korean guidelines. Therefore, our findings indicated that the QuEChERS method could be used as an effective alternative to conventional sample pretreatment for the analysis of herbal medicine ingredients.

Morphological changes in the trabecular meshwork and Schlemm's canal after treatment with topical intraocular pressure-lowering agents.

Glaucoma treatment is usually initiated with topical medication that lowers the intraocular pressure (IOP) by reducing the aqueous production, enhancing the aqueous outflow, or both. However, the effect of topical IOP-lowering medications on the microstructures of the aqueous outflow pathway are relatively unknown. In this retrospective, observational study, 56 treatment-naïve patients with primary open-angle glaucoma were enrolled. Images of the nasal and temporal corneoscleral limbus were obtained using anterior segment optical coherence tomography (AS-OCT). The conjunctival vessels and iris anatomy were used as landmarks to select the same limbal area scan, and the trabecular meshwork (TM) width, TM thickness, and Schlemm's canal (SC) area were measured before and after using the IOP-lowering agents for 3 months. Among the 56 patients enrolled, 33 patients used prostaglandin (PG) analogues, and 23 patients used dorzolamide/timolol fixed combination (DTFC). After 3 months of DTFC usage, the TM width, TM thickness, and SC area did not show significant changes in either the nasal or temporal sectors. Conversely, after prostaglandin analog usage, the TM thickness significantly increased, and the SC area significantly decreased (all P < 0.01). These findings warrant a deeper investigation into their relationship to aqueous outflow through the conventional and unconventional outflow pathways after treatment with PG analogues.