Erythromycin A is a clinically important macrolide antibiotic with broad-spectrum activity. Its biosynthesis involves the formation of the 14-membered skeleton catalyzed by polyketide synthases, and the modification steps such as hydroxylation, glycosylation and methylation. Based on the understanding of the biosynthetic mechanism, it is reliable to genetically manipulate the erythromycin A-producing strain for production improvement and structure modification. In this paper, we reviewed the progress regarding erythromycin A in high-producing strain construction and chemical structure derivation, to provide insights for further development.
Anti-Bacterial Agents ; biosynthesis ; chemistry ; Erythromycin ; biosynthesis ; chemistry ; Glycosylation ; Hydroxylation ; Methylation ; Multigene Family ; Polyketide Synthases ; metabolism

Objective To explore the risk factors related to postoperative recurrence of uterine fibroid following myomectomy.Methods Four hundred and seventy-three uterine fibroid patients underwent myomectomy were recruited in the case-control study.Leiomyoma characteristics,surgical approach,pathological type and follow-up information were collected by questionnaire.Data were analyzed by correlation analysis and multivariate conditional logistic regression analysis.The calculation of the risk factors associated with the degree of the recurrence after myomectomy was OR and its 95％ confidence interval (95％ CI).Results Among patients,194 cases with recurrence were detected after the 2-7 years follow-up.The number of fibroid removed was the risk factor of postoperative recurrence (OR =2.31,95％ CI:1.57-3.40,P =0.000).Compared with the single fibroid,the risk of recurrence increased 2.31 times in those patients who removed more than two fibroids.Preoperative parity was the protective factor for recurrence (OR =0.63,95％ CI:0.48-0.84,P =0.002).Neither age nor surgical approach or pathological type was associated with the risk of postoperative recurrence related to uterine fibroid following myomectomy.Conlcusion Fibroid number was the risk factor of postoperative recurrence while the preoperative parity was the protective factor.Laparoscopic myomectomy,cellular leiomyoma and muscle intramural leiomyoma did not increase the risk of recurrence.

Objective To explore the expression and significance of 25-hydroxy vitamin D [25(OH)D] in rheumatic disease patients,and its association with the risk of cardiovascular disease (CVD).Methods The level of 25(OH)D,bone mineral density (BMD) test and clinical indicators of 134 rheumatic disease cases were analyzed retrospectively.T test was used for statistical analysis.Results Patients who were combined with CVD and rheumatic disease,the level of 25-hydroxy vitamin D was (13±8) ng/ml,who were without CVD the level was (14±8) ng/ml.There was no significant difference between two groups(t=0.638,P＞0.05).But patients who were complicated with CVD and rheumatic diseases,their TC,TG,high-density lipoprotein cholesterol (HDL-C),low-density lipoprotein cholesterol (LDL-C),apolipoprotein (Apo) A,ApoB and lipoprotein levels were higher than patients who were without CVDs (t=3.314,3.397,3.092,2.159,3.621,2.011,2.066,both P＜0.05),and their BMD was lower than patients who were without CVDs (t=-16.131,P＜0.05).Conclusion To a certain extent,serum 25(OH)D levels of patients with rheumatic diseases is associated with CVD.

Objective:To analyze clinical characteristics of ketosis-associated prurigo pigmentosa after ketogenic diet and bariatric surgery.Methods:Clinical data were collected from patients with ketosis-associated prurigo pigmentosa, who were diagnosed and treated in Department of Dermatology, Peking University People′s Hospital from September 2018 to September 2020. The clinical characteristics, sequelae and therapeutic effect of dietary modification were analyzed and summarized.Results:A total of 6 patients with ketosis-associated prurigo pigmentosa were collected, including 5 females who developed prurigo pigmentosa after ketogenic diet, and 1 male who developed prurigo pigmentosa after bariatric surgery. The skin lesions mainly involved the chest, back, waist and abdomen, and rarely involved the eyelids, axillae, elbows and mons pubis. Common skin lesions included urticaria-like erythema, papules and pigmentation arranged in a reticular distribution, and rare skin lesions included mung bean- to soybean-sized blisters, whose walls were liable to break. Among 5 patients undergoing routine urine analysis, 4 were positive (from + to ++++) for ketone bodies in the urine, and 3 were positive for urinary protein (+) . Pathological examination in 2 patients showed epidermal spongiosis, scattered necrotic keratinocytes, basal cell liquefaction, lymphocyte infiltration in the superficial dermis, and erythrocyte extravasation. The 6 patients were advised to eat staple foods. After dietary modification, 5 patients were nearly cured within 1 week; 1 patient, who continued ketogenic diet for weight loss, still received marked improvement after the treatment with minocycline at a dose of 100 mg/d in spite of restriction of carbohydrate intake. The levels of urinary ketone bodies and urinary protein in the 6 patients all returned to normal within 1 week after treatment.Conclusions:Ketosis plays an important role in the occurrence of prurigo pigmentosa. Dietary modification alone or adjuvant medical treatment such as minocycline is effective for the treatment of ketosis-related prurigo pigmentosa.

AIM: The purpose of the present study was to examine the effect of insulin and different kinds of free fatty acid (FFA) on glucose transport in cultured 3T3-L1 preadipocytes or adipocytes. METHODS: Following the exposure of preadipocytes to insulin at different concentrations and treated times, glucose transport was assessed as [3H]2-deoxy glucose uptake. Furthermore, 3T3-L1 preadipocytes and adipocytes with either the monounsaturated FFA oleate (C18:1) or the saturated FFA palmitate (C16:0)were used and glucose transport was examined as above. RESULTS: Insulin increased specific membrane glucose transport in 3T3-L1 preadipocytes at the time of 15 min to 1 h stimulation. However, after 6 h exposure to insulin, downregulation of glucose transport was observed. Dose response studies demonstrated that 2-DG transport increased by 336% at 50 nmol/L of insulin (P

Objective To evaluate the development of cerebral sulci and gyrus in fetuses with conotruncal defect(CTD) at the second and third trimester by ultrasound,and to improve clinician′s understanding of the cerebral cortical development in fetuses with CTD.Methods The study was conducted at Shenzhen Maternity and Child Healthcare Hospital Affiliated to Southern Medicial University from December 2015 to January 2017,enrolled 180 women with single fetus,among whom 60 fetuses with CTD and gestational age between 20 weeks to 33+6 weeks were diagnosed by echocardiographic examination.CTD included persistent truncus arteriosous,tetralogy of fallot,transpofition of the great arteries and double outlet of right ventricle.Evaluation indexes of cerebral sulci and gyrus included depth and angle of parietooccipital sulcus,width and depth of sylvian fissure,uncovered width of insular,uncovered insular ratio,depth of calcarine sulcus,head circumference;evaluation indexes of hemodynamics included umbilical artery resistance index,umbilical artery pulsation index,middle cerebral artery resistance index,middle cerebral artery pulsation index,the cerebral-to-placental resistance ratio and the cerebroplacental pulsation ratio.Above indexes were measured for statistical analysis.Results At the whole gestational age in the study,depth of parietooccipital sulcus and width of sylvian fissure in CTD fetuses were smaller than those in the control group,uncovered insular ratio was larger than that in the normal group(P<0.05);middle cerebral artery resistance index,middle cerebral artery pulsation index and the cerebroplacental pulsation ratio in CTD fetuses were lower than those of the control group (P<0.05).Conclusions The change of hemodynamics in fetuses with CTD may be one of the reasons that fetuses with CTD have cerebral cortical hypoevolutism.

Objective To investigate the association between rs7744 polymorphism in the 3'?untranslated region(3'?UTR)of myeloid differen?tiation factor 88(MyD88)gene and the risk and severity of coronary artery disease(CAD)in a North Chinese Han population. Methods The CAD and control groups consisted of 540 patients and 270 subjects,respectively. The genotypes of rs7744 were detected by polymerase chain reac?tion?restriction fragment length polymorphism(PCR?RFLP),and clinical data were collected. Results The distributions of MyD88 rs7744 were in HWE(P>0.1). In the<50?year?old age group,a lower risk of CAD was observed for subjects carrying the variant AG genotype in comparison to subjects carrying the wild AA genotype(OR=0.38,95%CI:0.17-0.93,P=0.029). The MyD88 rs7744 polymorphism was also related to the modified Gensini score(P=0.011),which was lower in subjects carrying the variant GG genotype than the wild AA genotype(5.23±3.85 vs 7.49± 4.96). Conclusion Our results revealed that MyD88 rs7744 polymorphism in the 3'?UTR is correlated with the risk and severity of CAD.

To improve students' experimental research skills,innovative consciousness,promote the construction of functional experimental center,we established series of “comprehensive,contrivable,innovative” experiments in medical students.

In this study,we summarized the results from the retrospective investigation on endemic situation of schistosomia-sis that was implemented in nine provinces(autonomous region),China in 2009,demonstrated the role of these retrospective in-vestigations in accelerating the progress of schistosomiasis control in China,and clarified the great significance of the investiga-tion for summarizing the experiences for the control of schistosomiasis,and analyzing the changing patterns and affecting factors of endemic status of schistosomiasis in China. In addition,these retrospective investigations provide reliable evidence for revis-ing the Criteria of Schistosomiasis Control and Elimination,and for the more accurate and scientific assessment of the effec-tiveness of schistosomiasis control in China.

Objective To observe the variation of phosphatidylinositol-3 kinase (PI3K),protein kinase B (AKT),sodium iodide symporter (NIS) mRNA and protein expression in rat mammary tissues and serum insulin growth factor Ⅰ (IGF-1) under different iodine nutrition levels,and to study the role of PI3K-AKT signaling pathway in the process of mammary gland intaking iodine during lactation period.Methods Totally 130 Wistar rats (100 female rats,30 male rats) were randomly divided into five groups with 20 female rats in each group:①control group (NI):was feed with normal diet and iodine content 50 μg/L in deionized water;②low iodine group 1 (LI1 group):was feed with low iodine diet and deionized water;③low iodine group 2 (LI2):was feed with low iodine diet and iodine content 5 μg/L in deionized water;④high iodine group 1 (HI1 group):was feed with normal diet and iodine content 3 000 μg/L in deionized water;⑤high iodine group 2 (HI2):was feed with normal diet and iodine content 10 000 μg/L in deionized water.After feeding for 3 months,females were mated with male rats,then male rats were taken out and every female rat was feed individually.Urinary iodine level of rats in lactation period 10 days after giving birth was tested.Blood and mammary tissue samples of rats in lactation period were taken after killing them.Enzyme linked immunosorbent assay (ELISA) was used to detect serum IGF-1 level,real-time fluorescence quantification PCR to detect the mRNA expression of mammary gland PI3K,AKT and NIS,Western blotting to detect mammary gland PI3K,total AKT,phosphorylation AKT (p-AKT) and NIS protein expression.Results The medians urinary iodine of lactation period rats in LI1 and LI2 (3.16,6.36 μg/L) were significantly lower than that in NI group (162.59 μg/L),and were significantly higher in HI1 and HI2 (2 356.27,11 507.29 μg/L) than that in NI group.The differences were statistically significant (all P ＜ 0.01).Compared with control group [(8.84 ± 2.12) μg/L],the content of serum IGF-1 increased significantly in lactation period rats in LI1 and LI2 groups [(13.30 ± 2.37) and (10.90 ± 1.92) μg/L,all P＜ 0.01].The real-time fluorescence quantification PCR detection results indicated that the differences were statistically significant by comparing NIS,AKT,PI3K mRNA expression of the mammary tissues of lactation period rats in the five groups (F=14.916,36.477,14.994,all P＜ 0.01).Among them,NIS mRNA expression quantities in LI1 and LI2 groups (0.75 ± 0.40,0.89 ± 0.51) were significantly higher than that in NI group (0.53 ± 0.31),and significantly lower in HI2 group (0.30 ± 0.24) than that in NI group (P ＜ 0.05 or ＜ 0.01).AKT mRNA expression quantities in LI1 and LI2 groups (0.90 ± 0.19,0.64 ± 0.22) were significantly higher than that in NI group (0.43 ± 0.22),and significantly lower in HI2 group (0.29 ± 0.15) than that in NI group (P ＜ 0.05 or ＜ 0.01).PI3K mRNA expression quantity in LI1 group (0.85 ± 0.42) was significantly higher than that in NI group (0.50 ± 0.24),and significantly lower in HI2 group (0.28 ± 0.10) than that in NI group (all P ＜ 0.01).Western blot detection results indicated that the differences were statistically significant by comparing mammary gland NIS protein expression of lactation period rats in the five groups (F=4.510,P＜ 0.01).Among them,LI1 group (1.67 ± 0.97) was significantly higher than NI group (0.87 ± 0.43,P ＜ 0.05).The differences were statistically significant by comparing the p-AKT protein expression among groups (F =3.528,P ＜ 0.05).Among them,HI2 group (1.10 ± 0.30) was significantly higher than NI group (0.75 ± 0.23,P ＜0.05).The differences were not statistically significant by comparing total AKT and PI3K protein expression among groups (F =0.558,1.319,all P ＞ 0.05).Conclusion The inhibitory effect of PI3K-AKT signaling pathways on NIS in the mammary gland was weaker than the effect of iodine intake.But the expression of functional p-AKT was gradually increased with the increment of iodine intake,which had been presented inhibit effect on NIS expression in lactating mammary gland.