The efficient production of L-glutamate is dependent on the product's rapid efflux, hence researchers have recently concentrated on artificially modifying its transport system and cell membrane wall structure. Considering the unique composition and structure of the cell wall of Corynebacterium glutamicum, we investigated the effects of CmpLs on L-glutamate synthesis and transport in SCgGC7, a constitutive L-glutamate efflux strain. First, the knockout strains of CmpLs were constructed, and it was confirmed that the deletion of CmpL1 and CmpL4 significantly improved the performance of L-glutamate producers. Next, temperature-sensitive L-glutamate fermentation with the CmpL1 and CmpL4 knockout strains were carried out in 5 L bioreactors, where the knockout strains showcased temperature-sensitive characteristics and enhanced capacities for L-glutamate production under high temperatures. Notably, the CmpL1 knockout strain outperformed the control strain in terms of L-glutamate production, showing production and yield increases of 69.2% and 55.3%, respectively. Finally, the intracellular and extracellular metabolites collected at the end of the fermentation process were analyzed. The modification of CmpLs greatly improved the L-glutamate excretion and metabolic flux for both L-glutamate production and transport. Additionally, the CmpL1 knockout strain showed decreased accumulation of downstream metabolites of L-glutamate and intermediate metabolites of tricarboxylic acid (TCA) cycle, which were consistent with its high L-glutamate biosynthesis capacity. In addition to offering an ideal target for improving the stability and performance of the industrial strains for L-glutamate production, the functional complementarity and redundancy of CmpLs provide a novel target and method for improving the transport of other metabolites by modification of the cell membrane and cell wall structures in C. glutamicum.
Corynebacterium glutamicum/genetics* ; Glutamic Acid/biosynthesis* ; Fermentation ; Metabolic Engineering ; Bacterial Proteins/metabolism* ; Bioreactors/microbiology* ; Gene Knockout Techniques

Objective To investigate the causes for the continuous detection of Pseudomonas fluorescens(P.fluo-rescens)from bronchoalveolar lavage fluid(BALF)in pediatric department of a hospital,formulate intervention measures and evaluate its effectiveness,and provide basis for improving the whole process infection control of fiber bronchoscopy.Methods Epidemiological investigation was conducted on three children from whose BALF P.fluorescens were detected in May 3-6,2024.The comprehensive methods were adopted,including case revie-wing,on-site process tracking,environmental hygiene monitoring,laboratory testing on disinfectant sterilization effect,fiber bronchoscope structure maintenance and checking,etc.Risks were identified and targeted interventions were implemented.Results Among the 5 pediatric patients who underwent fiber bronchoscopy within 4 days,P.fluorescens was detected from BALF of 3 cases,with a detection rate of 60.0％.The children were 5-8 years old and were admitted to the hospital due to lobar pneumonia.They underwent fiber bronchoscopy from the day of admission to the second day,and bacterial strains were clinically determined to be contaminated strains.Environ-mental sampling showed that the detection rate of P.fluorescens at sampling points such as fiber bronchoscope and enzyme solution storage tank was 15.7％(8/51).After implementing intervention,no target bacteria were detected again,and the difference was statistically significant(P＜0.05).From January 1 to May 2,2024,71 BALF from pediatric department were not detected P.fluorescens;From May 3 to 6,among 5 detected BALF,3 were detected P.fluorescens;After intervention(May 16 to December 31),no specimen was detected P.fluorescens.Conclusion This event is a pseudo-outbreak caused by fiber bronchoscope damage as well as improper cleaning and disinfection procedures.Through collaborative investigation and timely intervention by multiple departments,the event was ef-fectively controlled.

Objective:To investigate the effect of β-Ecdysterone (β-Ecd), an active ingredient in cow′s knee, on hormonal femoral head necrosis in young rabbits and explore the mechanism involved.Methods:An animal study.Sixty New Zealand young rabbits were divided into control, model and intervention groups by random number table method, with 20 rabbits in each group.Prednisolone acetate (7.5 mg/kg) was injected bilaterally into the gluteal muscle of rabbits in both model and intervention groups twice a week.β-Ecd (0.5 mg/kg) was injected subcutaneously at the time of the first injection of Prednisolone acetate in the intervention group for 5 times a week.An equal amount of saline was injected into rabbits in control and model groups.Eight weeks after modelling, animals were put to death, and femoral heads were taken from both sides for gross observation.Micro computed tomography(Micro-CT) was used to analyze the microstructure of bone trabeculae and to measure bone microstructural parameters.Histological staining was used to detect changes in the morphology of bone tissues.Immunohistochemistry and Western blot were used to examine the expression of osteogenic and lipogenic factors and proteins in the femoral head tissue.Rabbit bone marrow mesenchymal stem cells (BMSCs) were divided into a blank control group, a Dexamethasone group and a β-Ecd intervention group.Cell damage was induced by Dexamethasone in Dexamethasone group and β-Ecd intervention group, and the β-Ecd intervention group was given the optimal concentration of β-Ecd.Western blot was used to detect the expression of osteogenic and lipogenic proteins in the cells of each group.Real-time quantitative polymerase chain reaction (RT-qPCR) was used to determine the mRNA expression of osteogenic and lipogenic marker genes.Results:After excluding 9 rabbits that died during the experimental period, 51 rabbits were finally included in the study, with 19 in the control group, 15 in the model group and 17 in the intervention group.Gross observation and Micro-CT showed that compared with that of the control group, the femoral head of the model group was obscure and greyish, with dark red necrotic areas.The bone trabeculae of the model group were sparse, thinned, disordered, and partially fractured, compared with those of the control group.The changes in the femoral head and bone trabeculae of the intervention group were between those of control and model groups.The bone mineral density, the number, thickness and relative volume of bone trabeculae significantly decreased and trabecular separation significantly increased in both model and intervention groups, compared with those in the control group ( F=12.78, 45.52, 32.74, 64.08, 8.83, all P<0.05).However, these symptoms in the intervention group were better than those in the model group.Pathological histology showed that in the control group, bone trabeculae were neatly arranged, robust and full, with a high number of osteoclasts and occasional empty bone sockets.In the model group, bone trabeculae were sparsely arranged and broken, with fewer osteoclasts, and the number of empty bone sockets increased and enlarged.In the intervention group, bone trabeculae had a more complete morphology, with fewer necrotic osteoclasts and reduced empty bone sockets, compared with the model group.Immunohistochemistry results showed that compared with the control group, the model group and intervention group had increased content of fatty acid binding proteins (FABP) and CCAAT/enhancer binding proteins α (CEBP) in the femoral head bone tissue, and decreased content of osteopontin (OPN) and Runt-related transcription factor 2 (RUNX2) .The changes in each index were greater in the model group than those in the intervention group ( F=21.07, 24.06, 17.92, 21.36, all P<0.05). Western blot detection showed that compared with the control group, the CEBP protein expression content of the femoral head in the model group and the intervention group was increased and the RUNX2 protein expression content was decreased. The changes of CEBP and RUNX2 were greater in the model group than those in the intervention group( F=73.43, 197.87, all P<0.05).Western blot detection of BMSCs showed that compared with the blank control group, the Dexamethasone group and β-Ecd intervention group had decreased expression of OPN and RUNX2 proteins and increased expression of FABP and CEBP proteins ( F=161.61, 358.01, 91.18, 69.04, all P<0.05).The changes in each index in the β-Ecd intervention group were smaller than those in the Dexamethasone group.RT-qPCR detection of BMSCs showed that in the Dexamethasone group had lower expression of OPN and RUNX2 and higher expression of CEBP and FABP than the blank control group ( F=19.71, 45.08, 61.46, 15.12, all P<0.05).The changes in each index in the β-Ecd intervention group were smaller than those in the Dexamethasone group. Conclusions:β-Ecd can attenuate the pathological changes of hormonal femoral head necrosis in young rabbits by promoting osteogenic differentiation of BMSCs, inhibiting lipogenic differentiation of BMSCs, and improving bone microstructure.

Objective To investigate the causes for the continuous detection of Pseudomonas fluorescens(P.fluo-rescens)from bronchoalveolar lavage fluid(BALF)in pediatric department of a hospital,formulate intervention measures and evaluate its effectiveness,and provide basis for improving the whole process infection control of fiber bronchoscopy.Methods Epidemiological investigation was conducted on three children from whose BALF P.fluorescens were detected in May 3-6,2024.The comprehensive methods were adopted,including case revie-wing,on-site process tracking,environmental hygiene monitoring,laboratory testing on disinfectant sterilization effect,fiber bronchoscope structure maintenance and checking,etc.Risks were identified and targeted interventions were implemented.Results Among the 5 pediatric patients who underwent fiber bronchoscopy within 4 days,P.fluorescens was detected from BALF of 3 cases,with a detection rate of 60.0％.The children were 5-8 years old and were admitted to the hospital due to lobar pneumonia.They underwent fiber bronchoscopy from the day of admission to the second day,and bacterial strains were clinically determined to be contaminated strains.Environ-mental sampling showed that the detection rate of P.fluorescens at sampling points such as fiber bronchoscope and enzyme solution storage tank was 15.7％(8/51).After implementing intervention,no target bacteria were detected again,and the difference was statistically significant(P＜0.05).From January 1 to May 2,2024,71 BALF from pediatric department were not detected P.fluorescens;From May 3 to 6,among 5 detected BALF,3 were detected P.fluorescens;After intervention(May 16 to December 31),no specimen was detected P.fluorescens.Conclusion This event is a pseudo-outbreak caused by fiber bronchoscope damage as well as improper cleaning and disinfection procedures.Through collaborative investigation and timely intervention by multiple departments,the event was ef-fectively controlled.

Objective:To investigate the effect of β-Ecdysterone (β-Ecd), an active ingredient in cow′s knee, on hormonal femoral head necrosis in young rabbits and explore the mechanism involved.Methods:An animal study.Sixty New Zealand young rabbits were divided into control, model and intervention groups by random number table method, with 20 rabbits in each group.Prednisolone acetate (7.5 mg/kg) was injected bilaterally into the gluteal muscle of rabbits in both model and intervention groups twice a week.β-Ecd (0.5 mg/kg) was injected subcutaneously at the time of the first injection of Prednisolone acetate in the intervention group for 5 times a week.An equal amount of saline was injected into rabbits in control and model groups.Eight weeks after modelling, animals were put to death, and femoral heads were taken from both sides for gross observation.Micro computed tomography(Micro-CT) was used to analyze the microstructure of bone trabeculae and to measure bone microstructural parameters.Histological staining was used to detect changes in the morphology of bone tissues.Immunohistochemistry and Western blot were used to examine the expression of osteogenic and lipogenic factors and proteins in the femoral head tissue.Rabbit bone marrow mesenchymal stem cells (BMSCs) were divided into a blank control group, a Dexamethasone group and a β-Ecd intervention group.Cell damage was induced by Dexamethasone in Dexamethasone group and β-Ecd intervention group, and the β-Ecd intervention group was given the optimal concentration of β-Ecd.Western blot was used to detect the expression of osteogenic and lipogenic proteins in the cells of each group.Real-time quantitative polymerase chain reaction (RT-qPCR) was used to determine the mRNA expression of osteogenic and lipogenic marker genes.Results:After excluding 9 rabbits that died during the experimental period, 51 rabbits were finally included in the study, with 19 in the control group, 15 in the model group and 17 in the intervention group.Gross observation and Micro-CT showed that compared with that of the control group, the femoral head of the model group was obscure and greyish, with dark red necrotic areas.The bone trabeculae of the model group were sparse, thinned, disordered, and partially fractured, compared with those of the control group.The changes in the femoral head and bone trabeculae of the intervention group were between those of control and model groups.The bone mineral density, the number, thickness and relative volume of bone trabeculae significantly decreased and trabecular separation significantly increased in both model and intervention groups, compared with those in the control group ( F=12.78, 45.52, 32.74, 64.08, 8.83, all P<0.05).However, these symptoms in the intervention group were better than those in the model group.Pathological histology showed that in the control group, bone trabeculae were neatly arranged, robust and full, with a high number of osteoclasts and occasional empty bone sockets.In the model group, bone trabeculae were sparsely arranged and broken, with fewer osteoclasts, and the number of empty bone sockets increased and enlarged.In the intervention group, bone trabeculae had a more complete morphology, with fewer necrotic osteoclasts and reduced empty bone sockets, compared with the model group.Immunohistochemistry results showed that compared with the control group, the model group and intervention group had increased content of fatty acid binding proteins (FABP) and CCAAT/enhancer binding proteins α (CEBP) in the femoral head bone tissue, and decreased content of osteopontin (OPN) and Runt-related transcription factor 2 (RUNX2) .The changes in each index were greater in the model group than those in the intervention group ( F=21.07, 24.06, 17.92, 21.36, all P<0.05). Western blot detection showed that compared with the control group, the CEBP protein expression content of the femoral head in the model group and the intervention group was increased and the RUNX2 protein expression content was decreased. The changes of CEBP and RUNX2 were greater in the model group than those in the intervention group( F=73.43, 197.87, all P<0.05).Western blot detection of BMSCs showed that compared with the blank control group, the Dexamethasone group and β-Ecd intervention group had decreased expression of OPN and RUNX2 proteins and increased expression of FABP and CEBP proteins ( F=161.61, 358.01, 91.18, 69.04, all P<0.05).The changes in each index in the β-Ecd intervention group were smaller than those in the Dexamethasone group.RT-qPCR detection of BMSCs showed that in the Dexamethasone group had lower expression of OPN and RUNX2 and higher expression of CEBP and FABP than the blank control group ( F=19.71, 45.08, 61.46, 15.12, all P<0.05).The changes in each index in the β-Ecd intervention group were smaller than those in the Dexamethasone group. Conclusions:β-Ecd can attenuate the pathological changes of hormonal femoral head necrosis in young rabbits by promoting osteogenic differentiation of BMSCs, inhibiting lipogenic differentiation of BMSCs, and improving bone microstructure.

Objective: To observe the clinical efficacy of electroacupuncture (EA) in controlling myopia in children and its effect on retinal blood flow. Methods: Sixty-eight myopic children were randomly divided into an observation group and a control group, with 34 cases in each group. The control group was given auricular acupressure treatment alone, and the observation group was treated with EA once a week in addition to the treatment used in the control group. The spherical equivalent refraction (SER) and axial length (AL) were measured at baseline, and after 3 months and 6 months of treatment. Optical coherence tomography angiography was used to measure the vessel density (VD) and perfusion density (PD) in the surface layer of the retina. Results: After 3 months and 6 months of treatment, the changes in SER between the two groups were not statistically significant (P>0.05). After 3 months of treatment, the changes in AL between the two groups were not statistically significant (P>0.05); after 6 months of treatment, the change amount of AL in the observation group was smaller than that in the control group (P<0.05); after 3 months and 6 months of treatment, the changes in VD and PD in the surface layer of the retina in the observation group were significantly greater than those in the control group (P<0.01). Conclusion: EA treatment once a week for 6 months can delay the increase of AL and improve the retinal surface blood flow in myopic children.

In the study of oral orthodontics, the dental tissue models play an important role in finite element analysis results. Currently, the commonly used alveolar bone models mainly have two kinds: the uniform and the non-uniform models. The material of the uniform model was defined with the whole alveolar bone, and each mesh element has a uniform mechanical property. While the material of the elements in non-uniform model was differently determined by the Hounsfield unit (HU) value of computed tomography (CT) images where the element was located. To investigate the effects of different alveolar bone models on the biomechanical responses of periodontal ligament (PDL), a clinical patient was chosen as the research object, his mandibular canine, PDL and two kinds of alveolar bone models were constructed, and intrusive force of 1 N and moment of 2 Nmm were exerted on the canine along its root direction, respectively, which were used to analyze the hydrostatic stress and the maximal logarithmic principal strain of PDL under different loads. Research results indicated that the mechanical responses of PDL had been affected by alveolar bone models, no matter the canine translation or rotation. Compared to the uniform model, if the alveolar bone was defined as the non-uniform model, the maximal stress and strain of PDL were decreased by 13.13% and 35.57%, respectively, when the canine translation along its root direction; while the maximal stress and strain of PDL were decreased by 19.55% and 35.64%, respectively, when the canine rotation along its root direction. The uniform alveolar bone model will induce orthodontists to choose a smaller orthodontic force. The non-uniform alveolar bone model can better reflect the differences of bone characteristics in the real alveolar bone, and more conducive to obtain accurate analysis results.
Biomechanical Phenomena ; Computer Simulation ; Finite Element Analysis ; Humans ; Models, Biological ; Periodontal Ligament ; Stress, Mechanical ; Tooth Movement Techniques

Objective: To assess clinical features and treatment outcomes in immunocompetent patients with primary central nervous system lymphoma (PCNSL). Methods: Sixty-two patients with PCNSL who attended Guangdong General Hospital between January 1998 and January 2012 were included. Survival curves were estimated using Kaplan-Meier survival methodology and statistical significance of continuous was assessed via the Cox proportional hazard model. Results: The median age of the patient cohort was 56 years, and the male to female ratio was 1.14∶1.00. The common presentations were increased intracranial pressure symptoms and neuron damage. Performance status of 54 (54/62, 87.1%) patients were the international prognostic index (IPI) 0-2. Diffuse large B-cell lymphoma (57/62, 91.9%) was most common, and the rest were T-cell lymphoma (4/62,6.4%) and extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (1/62, 1.6%). In the series, 32 patients (32/62, 51.6%) had multiple lesions. Involvement of deep structures was found in 30 (30/62, 48.4%) patients. An elevated serum LDH level was detected in 19 (19/62, 30.6%) patients and the Ki-67 index was ≥90% in 38 (38/62, 61.3%) patients. Univariate analysis showed patients who were female, age<60 years, had WHO Eastern Cooperative Oncology Group performance status grade 0-2, single lesion, absence of deep structures involvement and normal LDH level showed better 2-year survival rate and longer median survival time. Significance was only seen in the normal LDH level group. Multivariate Cox regression analysis revealed that radical surgery only and Rituximab+ high-dose of methotrexate+ whole brain radiation therapy (WBRT) were independent prognostic indicators in PCNSL patients (P<0.05). Conclusions PCNSL is a rare but aggressive tumor with poor prognosis. Patients treated with high-dose of methotrexate combining with rituximab, followed by WBRT have a better prognosis and longer survival time, and thus these could probably be a promising treatment.

Mandible is an important bone of the head and neck. Mandibular defects not only affect patient's face, but also impede patient's daily functions, such as chewing, speech, and so on. Fibular transplantation for mandibular reconstruction is the common method, which requests high accuracy of bone positioning and posture adjustment. Therefore, a robotic system for mandibular reconstruction surgery with fibula flaps was designed to assist surgeons to hold and locate bones, and the model comparison experiments were conducted. The results showed that the robotic system can assist surgeons for mandibular reconstruction to improve quality of surgery.
Bone Transplantation ; methods ; standards ; Fibula ; transplantation ; Humans ; Mandible ; surgery ; Mandibular Reconstruction ; methods ; Robotics ; standards ; Surgery, Computer-Assisted

assess clinical features and treatment outcomes in immunocompetent patients with primary central nervous system lymphoma (PCNSL). Methods Sixty?two patients with PCNSL who attended Guangdong General Hospital between January 1998 and January 2012 were included. Survival curves were estimated using Kaplan?Meier survival methodology and statistical significance of continuous was assessed via the Cox proportional hazard model. Results The median age of the patient cohort was 56 years, and the male to female ratio was 1.14∶1.00. The common presentations were increased intracranial pressure symptoms and neuron damage. Performance status of 54 (54/62, 87.1%) patients were the international prognostic index (IPI) 0-2. Diffuse large B?cell lymphoma (57/62, 91.9%) was most common, and the rest were T?cell lymphoma (4/62, 6.4%) and extranodal marginal zone lymphoma of mucosa?associated lymphoid tissue (1/62, 1.6%). In the series, 32 patients (32/62, 51.6%) had multiple lesions. Involvement of deep structures was found in 30 (30/62, 48.4%) patients. An elevated serum LDH level was detected in 19 (19/62, 30.6%) patients and the Ki?67 index was ≥90% in 38 (38/62, 61.3%) patients. Univariate analysis showed patients who were female, age<60 years, had WHO Eastern Cooperative Oncology Group performance status grade 0-2, single lesion, absence of deep structures involvement and normal LDH level showed better 2?year survival rate and longer median survival time. Significance was only seen in the normal LDH level group. Multivariate Cox regression analysis revealed that radical surgery only and Rituximab+ high?dose of methotrexate+ whole brain radiation therapy (WBRT) were independent prognostic indicators in PCNSL patients (P<0.05). Conclusions PCNSL is a rare but aggressive tumor with poor prognosis. Patients treated with high?dose of methotrexate combining with rituximab, followed by WBRT have a better prognosis and longer survival time, and thus these could probably be a promising treatment.