Topic Modeling Analysis of Chinese Medicine Literature on Gastroesophageal Reflux Disease: Insights into Potential Treatment.

OBJECTIVE: To analyze Chinese medicine (CM) prescriptions for gastroesophageal reflux disease (GERD), we model topics on GERD-related classical CM literature, providing insights into the potential treatment. METHODS: Clinical guidelines were used to identify symptom terms for GERD, and CM literature from the database "Imedbooks" was retrieved for related prescriptions and their corresponding sources, indications, and other information. BERTopic was applied to identify the main topics and visualize the data. RESULTS: A total of 36,207 entries are queried and 1,938 valid entries were acquired after manually filtering. Eight topics were identified by BERTopic, including digestion function abate, stomach flu, respiratory-related symptoms, gastric dysfunction, regurgitation and gastrointestinal dysfunction in pediatric patients, vomiting, stroke and alcohol accumulation are associated with the risk of GERD, vomiting and its causes, regurgitation, epigastric pain, and symptoms of heartburn. CONCLUSIONS: Topic modeling provides an unbiased analysis of classical CM literature on GERD in a time-efficient and scale-efficient manner. Based on this analysis, we present a range of treatment options for relieving symptoms, including herbal remedies and non-pharmacological interventions such as acupuncture and dietary therapy.

[Directed evolution of D-lactonohydrolase by error prone PCR and DNA shuffling].

D-lactonohydrolase is useful in the procedure of resolution of racemic pantolactone to produce D-pantolactone, but the activity and stability under low pH of the wild type enzyme is not satisfactory enough to be applied to industrial production. The expected properties of wild type enzyme were enhanced by directed evolution. According to the formation of products and pH indicators, a screening system was designed. After three sequential error prone PCR and one round DNA shuffling followed by screening, Mut E-861, the best mutant with improved activity and stability under low pH situation was obtained. Gene analysis of the Mut E-861 mutant indicated that the mutant enzyme had A352C, G721A mutations and a silent mutation of position 1038. Moreover, the activity and stability of Mut E-861 were determined. The results showed that the activity of this mutant was 5.5-fold higher than that of wild type, and the stability under low pH was improved at no expense of D-lactonohydrolase activity. After incubated at pH 6.0 and pH 5.0 the activity of D-lactonohydrolase could be retained 75% to 50%, however, compared with 40% to 20% for wild type.