NAD precursors cycle between host tissues and the gut microbiome.

Nicotinamide adenine dinucleotide (NAD) is an essential redox cofactor in mammals and microbes. Here we use isotope tracing to investigate the precursors supporting NAD synthesis in the gut microbiome of mice. We find that dietary NAD precursors are absorbed in the proximal part of the gastrointestinal tract and not available to microbes in the distal gut. Instead, circulating host nicotinamide enters the gut lumen and supports microbial NAD synthesis. The microbiome converts host-derived nicotinamide into nicotinic acid, which is used for NAD synthesis in host tissues and maintains circulating nicotinic acid levels even in the absence of dietary consumption. Moreover, the main route from oral nicotinamide riboside, a widely used nutraceutical, to host NAD is via conversion into nicotinic acid by the gut microbiome. Thus, we establish the capacity for circulating host micronutrients to feed the gut microbiome, and in turn be transformed in a manner that enhances host metabolic flexibility.

Frailty and Biological Age.

A reliable model of biological age is instrumental in the field of geriatrics and gerontology. This model should account for the heterogeneity and plasticity of aging and also accurately predict aging-related adverse outcomes. Epigenetic age models are based on DNA methylation levels at selected genomic sites and can be significant predictors of mortality and healthy/unhealthy aging. However, the biological function of DNA methylation at selected sites is yet to be determined. Frailty is a syndrome resulting from decreased physiological reserves and resilience. The frailty index is a probability-based extension of the concept of frailty. Defined as the proportion of health deficits, the frailty index quantifies the progression of unhealthy aging. The frailty index is currently the best predictor of mortality. It is associated with various biological factors and provides insight into the biological processes of aging. Investigation of the multi-omics factors associated with the frailty index will provide further insight.

[Comparison of the effectiveness of vertebral arch replantation and laminectomy in the treatment of mild to moderate isthmic spondylolisthesis].

OBJECTIVE: To compare the effectiveness of vertebral arch replantation and laminectomy in the treatment of mild to moderate isthmic spondylolisthesis. METHODS: The clinical data of 66 patients with isthmic spondylolisthesis treated with vertebral arch replantation or laminectomy between March 2014 and July 2016 were retrospectively analyzed. They were divided into trial group (34 cases, treated with complete replantation of vertebral arch, intervertebral fusion, and internal fixation) and control group (32 cases, treated with laminectomy with intervertebral fusion and internal fixation) according to different surgical methods. There was no significant difference in general data of gender, age, disease duration, lesion segment, Meyerding grade, and preoperative visual analogue scale (VAS) score, Oswestry disability index (ODI) score, Japanese Orthopaedic Association (JOA) score between the two groups ( P>0.05). The operation time, intraoperative blood loss, complications, vertebral arch fusion of trial group, and epidural scar formation of the two groups were recorded. The VAS score, JOA score, and ODI score were evaluated at preoperation, 3, 6, 12 months after operation, and at last follow-up. The effectiveness was evaluated according to HOU Shuxun's criteria. RESULTS: All the patients successfully completed the surgery, without any aggravation of nerve injury, dural tear, infection, etc. There was no significant difference in the operation time between the two groups ( t=0.583, P=0.562), but the intraoperative blood loss was significantly lower in the trial group than that in the control group ( t=2.134, P=0.037). All the 66 patients were followed up 13-18 months (mean, 16.2 months). Postoperative clinical symptoms of all patients were significantly improved. In the control group, 7 cases were found to have symptoms of spinal canal stenosis with postoperative posture changes at 3 months after operation, and 5 cases showed mild lower limb numbness at 18 months after operation. No complication such as infection and nerve injury occurred in other patients. In the trial group, 34 cases of epidural scar tissue were completely blocked outside the replantation vertebral arch, while in the control group, 11 cases of epidural scar tissue invaded the spinal canal. At last follow-up, the fusion rate of intervertebral bone grafting and vertebral arch replantation in the trial group was 100%, and the fusion rate of intervertebral bone grafting in the control group was also 100%. The VAS score, ODI score, and JOA score were significantly improved at each time point after operation ( P<0.01). The ODI score and JOA score of the trial group were significantly better than those of the control group at 3 months after operation and at last follow-up ( P<0.05), and there was no significant difference in scores between the two groups at other time points ( P>0.05). According to HOU Shuxun's criteria, the excellent and good rate was 91.2% in the trial group and 84.4% in the control group, showing no significant difference ( χ 2=1.092, P=0.573). CONCLUSION: Compared with laminectomy, vertebral arch replantation can better improve postoperative neurological symptoms, maximize the reconstruction of the bone spinal canal, restore the stability of the intraspinal environment, and it is a better surgical method for lumbar isthmic spondylolisthesis.

[Progress on surgical treatment of isthmic spondylolisthesis].

Isthmic spondylolisthesis is a common degenerative disease of the spine and seriously affects people's quality of life. At present, surgical indications for lumbar spondylolisthesis have basically reached consensus. The surgical plan for the disease is mainly isthmus repair, decompression of spinal canal, reduction of spondylolisthesis, and spinal fusion. The principle of treatment is mainly to relieve nerve compression and restore spinal stability, but for each the specific method and degree of implementation of the link still remains controversial. Open surgery can complete decompression, reduction and fusion of severe spondylolisthesis, and rebuild the stability of the spine. However, the surgical trauma is too large. Minimally invasive surgery can reduce the damage of paravertebral soft tissue, reduce intraoperative blood loss, shorten the time of hospitalization and rehabilitation, and reduce the incidence of intraoperative and postoperative complications. Therefore, in recent years, more and more clinicians praise it, but the treatment of severe spondylolisthesis lumbar spondylolisthesis is not effective. This article reviews recent advances in surgical treatment of lumbar spondylolisthesis.

Soleus muscle H-reflex monitoring in endoscopic surgery under general anesthesia percutaneous interlaminar approach.

The clinical value of soleus muscle H-reflex monitoring in general anesthesia percutaneous interlaminar approach was investigated. A total of 80 cases with unilateral L5-S1 disc herniation between January 2015 and October 2016 were randomly divided into control group (without soleus muscle H-reflex monitoring, n=40) and observation group (with soleus muscle H-reflex monitoring, n=40). Results showed that the operation time of the observation group was shorter than that of the control group (P<0.05), and the blood loss during the operation was less than that of the control group (P<0.05). The length of postoperative hospital stay was shorter than that of the control group (P<0.05). At 24 h after operation, the amplitude of H-reflex in diseased side soleus muscle was significantly lower than that in healthy side (P<0.05). The preoperative, postoperative and 24 h postoperatively, the latency of H-reflex in diseased side soleus muscle was shorter than that of healthy side (P<0.05). The latency and amplitude of H-reflex latency in soleus muscle were significantly lower (P<0.05), and the height of intervertebral space in observation group was significantly higher than that in control group (P<0.05). The total percentage of postsurgical sensory dysfunction, dyskinesia, post-root canal stenosis, disc herniation and cerebrospinal fluid leakage was lower than that of the control group (P<0.05). Japanese Orthopaedic Association score of the observation group was significantly higher at 1 month, and 1 year after operation lower than the control group (P<0.05). Taken together, soleus muscle H-reflex monitoring can effectively reduce the damage to the nerve roots under percutaneous endoscopic intervertebral endoscopic surgery under general anesthesia, improve the accuracy of surgery, reduce the complications, shorten the operation time and reduce the surgical bleeding, which is more beneficial to patients smooth recovery.

Three-dimensional spiral CT measurement of atlantal pedicle and its clinical application.

The study aimed to establish the safe placement area and corresponding entry angle of atlantal pedicle screw using axial computed tomography (CT) measurement of atlas, in order to guide the clinical operation. Spiral thin-slice CT scan of atlas and three-dimensional reconstruction of 38 patients were randomly selected. Screw placement space was defined as the distance between the tangent lines of entry channel on the atlantal cross section and inner edge of transverse foramen and outer edge of spinal canal. Before operation, spiral CT measurement was used to determine the safe placement area, and the pipeline dredge method was used to conduct the internal fixation of atlantal pedicle screw for 7 patients. In CT measurements, the width of pedicle was 9.15±2.57 mm, which could safely accommodate screws with the diameter of 3.5 mm. The safe placement area was located in posterior arch of atlas (18.35±2.86 to 25.26±1.76 mm) away from the posterior tubercle, the entry angle ranged from 9.09±7.45° outward to 18.72±17.42° inward, and the length of screw channel ranged from 26.20±2.69 to 27.04±2.51 mm. The width of the safe placement area was up to 6.91±7.66 mm, and the angle of inclination on cross section was up to 27.81±10.32°. In conclusion, we identified a safe placement area for atlantal pedicle screw, where the screw was implanted inwards and outwards according to different entry points within the safe placement area. The detailed preoperative image measurement, determination of safe placement area and individual screw placement were found to be the key to a successful surgery.

An LC-MS/MS method for simultaneous determination of hosenkoside A and hosenkoside K from Semen Impatientis in rat plasma and its application to a pharmacokinetic study.

A rapid and sensitive liquid chromatography tandem mass spectrometry (LC-MS/MS) method was developed and validated for the simultaneous determination of two baccharane glycosides (hosenkoside A and hosenkoside K) of total saponins of Semen Impatientis in rat plasma using mogroside V as the internal standard (IS). The analytes were separated using a C18 RP Agilent XDB column (1.8 µm, 50 × 2.1 mm i.d.) and detection of the compounds was done using a TSQ Quantum triple quadrupole mass spectrometer coupled with a negative electrospray ionization source under selection reaction monitoring mode. According to the US Food and Drug Administration guidelines, the established method was fully validated and the results were proved within acceptable limits. The lower limits of quantification of both analytes were 5 ng/mL. The validated method was successfully applied to a pharmacokinetic study of orally administered the total saponins of Semen Impatientis in rats.

Identification of transcriptional factors and key genes in primary osteoporosis by DNA microarray.

BACKGROUND: A number of genes have been identified to be related with primary osteoporosis while less is known about the comprehensive interactions between regulating genes and proteins. We aimed to identify the differentially expressed genes (DEGs) and regulatory effects of transcription factors (TFs) involved in primary osteoporosis. MATERIAL/METHODS: The gene expression profile GSE35958 was obtained from Gene Expression Omnibus database, including 5 primary osteoporosis and 4 normal bone tissues. The differentially expressed genes between primary osteoporosis and normal bone tissues were identified by the same package in R language. The TFs of these DEGs were predicted with the Essaghir A method. DAVID (The Database for Annotation, Visualization and Integrated Discovery) was applied to perform the GO (Gene Ontology) and KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway enrichment analysis of DEGs. After analyzing regulatory effects, a regulatory network was built between TFs and the related DEGs. RESULTS: A total of 579 DEGs was screened, including 310 up-regulated genes and 269 down-regulated genes in primary osteoporosis samples. In GO terms, more up-regulated genes were enriched in transcription regulator activity, and secondly in transcription factor activity. A total 10 significant pathways were enriched in KEGG analysis, including colorectal cancer, Wnt signaling pathway, Focal adhesion, and MAPK signaling pathway. Moreover, total 7 TFs were enriched, of which CTNNB1, SP1, and TP53 regulated most up-regulated DEGs. CONCLUSIONS: The discovery of the enriched TFs might contribute to the understanding of the mechanism of primary osteoporosis. Further research on genes and TFs related to the WNT signaling pathway and MAPK pathway is urgent for clinical diagnosis and directing treatment of primary osteoporosis.