Study on the effect of enzymatic treatment of tobacco on HnB cigarettes and microbial succession during fermentation.

Starch and cellulose are the fundamental components of tobacco, while their excessive content will affect the quality of tobacco. Enzymatic treatment with different enzymes is a promising method to modulate the chemical composition and improve the sensory quality of tobacco leaves. In this study, enzymatic treatments, such as amylase, cellulase, and their mixed enzymes, were used to improve tobacco quality, which could alter the content of total sugar, reducing sugar, starch, and cellulose in tobacco leaves. The amylase treatment changed surface structure of tobacco leaves, increased the content of neophytadiene in tobacco by 16.48%, and improved the total smoking score of heat-not-burn (HnB) cigarette products by 5.0 points compared with the control. The Bacillus, Rubrobacter, Brevundimonas, Methylobacterium, Stenotrophomonas, Acinetobacter, Pseudosagedia-chlorotica, and Sclerophora-peronella were found to be significant biomarkers in the fermentation process by LEfSe analysis. The Basidiomycota and Agaricomycetes were significantly correlated with aroma and flavor, taste, and total score of HnB. The results showed that microbial community succession occurred due to amylase treatment, which promoted the formation of aroma compounds, and regulated the chemical composition of tobacco, and improved tobacco quality during tobacco fermentation. This study provides a method for enzymatic treatment to upgrade the quality of tobacco raw materials, thereby improving the quality of HnB cigarettes, and the potential mechanism is also revealed by chemical composition and microbial community analysis. KEY POINTS: Enzymatic treatment can change the chemical composition of tobacco leaves. The microbial community was significantly affected by enzymatic treatment. The quality of HnB cigarettes was significantly improved by amylase treatment.

Clinical Characteristics and Treatment of Spontaneous Osteonecrosis of Medial Tibial Plateau: A Retrospective Case Study / 中华医学杂志(英文版)

<p><b>Background</b>In a small proportion of cases, spontaneous osteonecrosis of the knee (SONK) involves the medial tibial plateau (MT). Here, we introduced the clinical characteristics of spontaneous osteonecrosis of the MT and unicompartmental knee arthroplasty (UKA) as the favorable treatment for this situation based on a retrospective case study.</p><p><b>Methods</b>Patients with spontaneous osteonecrosis of the MT, confirmed by magnetic resonance imaging (MRI) at Guangdong Provincial Hospital of Chinese Medicine (China) from March 2015 to June 2016, were included as a case serial and analyzed retrospectively. All patients underwent Oxford Medial UKA. The characteristics of their lesions, corresponding treatment, and results of follow-up were presented. The lesion scores and grade were determined according to the criteria of Ficat and Arlet.</p><p><b>Results</b>In total, 22 patients (5 men, 17 women; mean age, 64.1 years) with spontaneous osteonecrosis of the MT were analyzed. The lesion stages assessment showed that 3 (14%) were Stage II, 10 (45%) were Stage III, 7 (32%) were Stage IV, and 2 (9%) were Stage V. In the sagittal plane, 7 (32%) were in the anterior region (MTa) and 15 (68%) were central (MTc). The lesion volume averaged 2.24 ± 0.79 cm (range: 1.57-3.08 cm). Seventeen patients (77%) had Level III posterior medial meniscus root tears (MMRTs). All the patients underwent UKA. Average follow-up was 30.0 ± 6.4 months with a range of 23.0-38.0 months. The visual analog scale score was 7.78 ± 0.67 before surgery while decreased to 2.22 ± 1.09 at the final follow-up (P < 0.001). The Hospital for Special Surgery scores of pre-/post-surgery were 65.67 ± 5.45 and 84.10 ± 4.20, respectively (P < 0.001).</p><p><b>Conclusions</b>SONK often occurs in the anterior and central tibial plateau due to abnormal stresses. Most of the patients had Level III posterior medial meniscus root tears. MRI is recommended for suspected cases to identify SONK at an early stage. The use of the Oxford Medial UKA for SONK of the MT is reliable both immediately and at follow-up.</p>