Discovery of Potent Glycosidases Enables Quantification of Smoke-Derived Phenolic Glycosides through Enzymatic Hydrolysis

When grapes are exposed to wildfire smoke, certain smoke-related volatile phenols (VPs) can be absorbed into the fruit, where they can be then converted into volatile-phenol (VP) glycosides through glycosylation. These volatile-phenol glycosides can be particularly problematic from a winemaking standpoint as they can be hydrolyzed, releasing volatile phenols, which can contribute to smoke-related off-flavors. Current methods for quantitating these volatile-phenol glycosides present several challenges, including the requirement of expensive capital equipment, limited accuracy due to the molecular complexity of the glycosides, and the utilization of harsh reagents. To address these challenges, we proposed an enzymatic hydrolysis method enabled by a tailored enzyme cocktail of novel glycosidases discovered through genome mining, and the generated VPs from VP glycosides can be quantitated by gas chromatography-mass spectrometry (GC-MS). The enzyme cocktails displayed high activities and a broad substrate scope when using commercially available VP glycosides as the substrates for testing. When evaluated in an industrially relevant matrix of Cabernet Sauvignon wine and grapes, this enzymatic cocktail consistently achieved a comparable efficacy of acid hydrolysis. The proposed method offers a simple, safe, and affordable option for smoke taint analysis.

0887 Diaphragm Pacer Malfunctions Requiring Surgical Repair in CCHS Patients

Introduction

Congenital Central Hypoventilation Syndrome (CCHS) is a genetic disorder that results in the loss of autonomic ventilatory control, and patients require ventilatory support during sleep or both sleep and wakefulness. One method of ventilatory support is diaphragm pacing (DP), where electrodes surgically placed on the phrenic nerve are connected to subcutaneously implanted receivers that communicate with external antennas and transmitter. There are limited data on the frequency of DP malfunctions that require surgical revision.

Methods

We reviewed the records of 24 CCHS patients ventilated by DP followed at CHLA from 1990-2019. Records were examined for demographics, PHOX2B mutation, pacing duration/day, date and type of malfunctions, age and time since implantation at malfunction occurrence, and repair success rate.

Results

All 24 patients had thoracoscopic electrode placement. 17/24 (71%) of patients used DP while asleep; 3/24 (13%) during wakefulness only. 4/24 (17%) were not currently using their pacers. 10/24 (42%) patients required at least one surgical intervention (Age at implantation 9 ± 4.6 (SD) years; age at malfunction 12.5 ± 7.4 years). The average time from pacer implantation to malfunction was 3.8 ± 3.5 years. Malfunctions included defective receivers (6), insulation leaks (1), defective electrodes (4), and hardware infection (1). Of 12 unique component repairs, 6/12 (50%) involved changing receivers, 1/12 (8%) involved repairing an insulation leak, 4/12 (33%) involved replacing the electrodes and receivers, and 1/12 (8%) involved hardware extraction. Of the 12 malfunctions, 10 (83%) had successful surgical revision. 2/12 (17%) repairs were not attempted. While awaiting surgical revision, patients were successfully ventilated by unilateral DP.

Conclusion

Nearly half of CCHS patients on DP experienced malfunctions within 11 years of implantation. The most common DP repair was receiver replacement. Patients who are waiting for repair often successfully ventilate while pacing unilaterally.

Support

None

0874 Patients with Congenital Central Hypoventilation Syndrome Do Not Wake Up to Ventilator Alarms

Introduction

Congenital Central Hypoventilation Syndrome (CCHS) requires lifelong ventilatory support during sleep. CCHS patients are vulnerable to sleep disturbances associated with treatments, monitoring alarms, and care they receive. We hypothesized that sleep would be disrupted in CCHS patient’s due to ventilatory support and other treatments at night.

Methods

An anonymous survey of CCHS patients aged 0-17 years was conducted through REDCAP. Patients were recruited in person, by flyer, email, and social media. Data collected included demographics, PHOX2B genotype, ventilatory support, treatments, nursing, and sleep parameters.

Results

We received 22 responses (27% Female, 8.1 years ± 5.7). PHOX2B genotypes were 20/27 PARM (8), 20/26 PARM (2), 20/24 PARM (2), 20/25 PARM (4), ≥ 20/28 PARM (2), and 2 NPARM (2). Two respondents did not indicate the PHOX2B genotype. 13/22 were ventilated by PPV via tracheostomy, 7/22 by BPAP, and 2/22 by diaphragm pacing. Additional treatments received at night included suctioning (8), aerosol (1), G-tube feeding (2), and none (11). Only 9 received nursing at night. 13 used pulse oximetry for monitoring, and 9 used both pulse oximetry and end tidal CO2 monitor. 16/22 rarely woke up due to ventilator or monitor alarms. 15/22 slept within 20 minutes after going to bed. Sleep latency was not affected by mode of ventilation. 11/22 reported night waking ≥ 2 nights/week and 10/22 returned to sleep without help after night waking. 6/7 BPAP dependent patients reported low frequency of night waking (0-1 time/week). Of the PPV + trach group, 7/13 reported high frequency of night wakings, mostly 5-7 times/week.

Conclusion

Most CCHS patients do not awaken in response to ventilator alarms. Sleep is rarely disrupted by nursing or feeding intervention. We speculate that CCHS patients contemplating to live independently should be tested to see if they awaken in response to ventilator alarms.

Support

None