Electrical modulation properties of DNA drug molecules.

DNA drug molecules are not only widely used in gene therapy, but also play an important role in controlling the electrical properties of molecular electronics. Covalent binding, groove binding and intercalation are all important forms of drug-DNA interaction. But its applications are limited due to a lack of understanding of the electron transport mechanisms after different drug-DNA interaction modes. Here, we used a combination of density functional theory calculations and nonequilibrium Green's function formulation with decoherence to study the effect of drug molecules on the charge transport property of DNA under three different binding modes. Conductance of DNA is found to decrease from 2.35E-5 G0 to 1.95E-6 G0 upon doxorubicin intercalation due to modifications of the density of states in the near-highest occupied molecular orbital region, δG = 1105.13%. Additionally, the conductance of DNA after cis-[Pt(NH3)2(py)Cl]+ covalent binding increases from 1.02E-6 G0 to 5.25E-5 G0, δG = 5047.06%. However, in the case of pentamidine groove binding, because there is no direct change in DNA molecular structure during drug binding, the conductance changes before and after drug binding is much smaller than in the two above cases, δG = 90.43%. Our theoretical calculations suggest that the conductance of DNA can be regulated by different drug molecules or switching the interaction modes between small molecules and DNA. This regulation opens new possibilities for their potential applications in controllable modulation of the electron transport property of DNA.

Nanoscale Insights into CO2 Enhanced Shale Gas Recovery in Gas-Water Coexisting Kerogen Nanopores.

The presence of water clusters in kerogen nanopores reduces the occurrence and migration of methane (CH4) and thus affects shale gas extraction. CO2 injection, as an effective approach to enhance shale gas recovery, still presents challenges in its ability to mitigate the impact of immobile water clusters within the kerogen. In this work, molecular dynamics simulations were employed to investigate the microscopic transport process of water clusters and CH4 following CO2 injection in the gas-water coexisting kerogen nanopores. The results demonstrate that CO2 can desorb irreducible water clusters to dredge the pores while extracting CH4, enhancing gas-water mobility, and shale gas recovery by transitioning the wettability of the kerogen nanopore surface from weakly water-wet to CO2-wet. The impact of CO2 on the wettability of kerogen surfaces is primarily manifested in two aspects: CO2 can intrude the interface between water clusters and kerogen to reduce the number of hydrogen bonds between them, resulting in the detachment of water clusters; and the surface of kerogen nanopores can form a layer of CO2 gas film, which prevents desorbed water clusters and CH4 from readsorbing onto the wall surface. This study provides important insights in enhancing the understanding of the microscopic mechanisms in nanoscale flow, as well as for the development of an unconventional gas reservoir.

Endoplasmic reticulum stress-mediated autophagy alleviates lipopolysaccharide-induced nucleus pulposus cell pyroptosis by inhibiting CHOP signaling in vitro.

Pyroptosis, a newly discovered pro-inflammatory programmed necrosis of cells, serves as an initiating and promoting event that leads to intervertebral disc (IVD) degeneration (IDD). Endoplasmic reticulum stress (ERS) and autophagy are vital regulatory mechanisms of cellular homeostasis, which is also closely related to IDD. However, the role and relationship of ERS and autophagy in the pyroptosis of nucleus pulposus cell (NPC) are not well understood. In this research, we aimed to elucidate the role and mechanism of ERS-C/EBP homologous protein (CHOP) in lipopolysaccharide (LPS)-induced cell pyroptosis and determine its interaction with autophagy. ERS and autophagy inducers or inhibitors were used or not in the preconditioning of rat NPCs. Cell viability, pyroptosis-related protein expression, caspase-1 activity assay, and enzyme-linked immunosorbent assay were performed to observe rat NPC pyroptosis after the treatment of LPS. Activation of the ERS pathway and autophagy were assessed by quantitative real-time PCR, western blot analyses, and immunofluorescence staining assay to classify the molecular mechanisms. Our results showed that LPS stimulation induced NPC pyroptosis with concomitant activation of the ERS-CHOP pathway and initiated autophagy. Activation of the ERS-CHOP pathway exacerbated rat NPC pyroptosis, whereas autophagy inhibited cell pyroptosis. LPS-induced cell pyroptosis and CHOP upregulation were negatively regulated by autophagy. LPS-induced autophagy was depressed by the ERS inhibitor but aggravated by the ERS inducer. Taken together, our findings suggested that LPS induced NPC pyroptosis by activating ERS-CHOP signaling and ERS mediated LPS-induced autophagy, which in turn alleviated NPC pyroptosis by inhibiting CHOP signaling.

Endoscopic-Assisted Forehead Augmentation with Polyetheretherketone (PEEK) Patient-Specific Implant (PSI) for Aesthetic Considerations.

BACKGROUND: Forehead augmentation have become popular aesthetic procedures among Asians in recent years. However, the use of polyetheretherketone (PEEK) patient-specific implant (PSI) in the facial contouring surgery for aesthetic considerations is not well documented in the existing studies. The purpose of this study was to develop a novel method for forehead augmentation and assess the clinical outcomes and complications in patients who underwent forehead augmentation with PEEK PSI assisted by endoscopy. METHODS: The PEEK PSIs were fabricated using the virtual surgical planning (VSP) and the computer-aided manufacturing (CAM) for each patient, preoperatively. The implant pockets were dissected in the subperiosteal plane, and PEEK PSIs were placed in their designed position and fixed assisting by endoscopy via small incision within the hairline. All patients were asked to complete the FACE-Q questionnaire before and 6 months after the operation. Pre- and postoperative demographics, photographs, and other clinical data of patients were collected and analyzed. RESULTS: 11 patients underwent forehead augmentation were enrolled in this study. All procedures were completed successfully with the help of endoscope. The average patient age was 30.63 ± 2.54 years. The mean thickness and size of PEEK PSI were 4.44 ± 1.77 mm and 38.43 ± 22.66 cm2, respectively. The mean operative time was 83.00 ± 29.44 min, and the mean postoperative follow-up period was 11.00 ± 6.50 months. No implant exposure, extrusion or removal were reported. The FACE-Q scores of patients in satisfaction with the forehead increased from 47.64 ± 7.15 to 78.81 ± 6.35. CONCLUSIONS: PEEK PSIs can be prefabricated to achieve accurate remodeling of the frontal contour with good esthetic outcomes. The endoscope provides direct and magnified vision, which allow easy access to the supraorbital rim and lateral edge of the eyebrow arch and confirming the position of the implants without damaging nerves and vessels. Endoscopic-assisted forehead augmentation with PEEK PSI is safe and effective. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these evidence-based medicine ratings, please refer to the Table of contents or the online Instructions to Authors www.springer.com/00266 .

Bioinformatics Analysis and Identification of Ferroptosis-Related Hub Genes in Intervertebral Disc Degeneration.

Approximately 80% of individuals encounter lower back pain (LBP), a prevalent clinical issue largely attributed to intervertebral disc degeneration (IDD). Ferroptosis is an iron-dependent lipid peroxidation-driven cell death, and there is growing evidence that ferroptosis plays an important role in various human diseases. However, the underlying mechanism of ferroptosis in IDD remains unclear. This study aims to reveal the potential hub genes and related pathways of ferroptosis in the pathogenesis and progression of IDD. In this study, we analyzed three microarray datasets from the GEO database. Additionally, we downloaded ferroptosis-related genes from FerrDb-V2 and extracted apoptosis-related genes from UniProt as a control to show the specificity of ferroptosis. Weighted gene co-expression network analysis (WGCNA) was performed to identify the IDD-related module genes. Then, ferroptosis-related genes and apoptosis-related genes were separately overlapped with the IDD-related module genes, resulting in the identification of 35 ferroptosis-related module genes (FRMG) and 142 apoptosis-related module genes (ARMG). Furthermore, we performed functional enrichment analysis and protein-protein interaction network, and Cytoscape along with CytoHubba was used to identify the hub genes. Finally, logistic regression models were constructed and identified two hub FRMGs (PTEN and EGFR) and one hub ARMG (CTNNB1), which could distinguish IDD patients from controls (P < 0.05). The areas under the ROC curves were 0.792 and 0.730, respectively, suggesting that ferroptosis is more specific than apoptosis in IDD. In conclusion, this study provided fresh perspectives on ferroptosis in the pathogenesis and progression of IDD that can be used to evaluate potential biomarker genes and therapeutic targets.

Correcting the Broad, Flat and Short Chin Using Modified M-genioplasty.

BACKGROUND: Several genioplasty techniques can narrow the width of the chin. Nevertheless, patients with a broad and short chin who received these methods were unsatisfied with the outcomes. The goal of this study was to analyze the clinical outcomes of modified M-shaped genioplasty for broad, flat and short chin deformity. METHODS: Thirty-eight patients with broad, flat and short chins were included in this study from January 2019 to December 2021. The preoperative design was performed individually according to the data of the chin and the patient's desire of final chin shape. Narrowing and vertical elongating genioplasty was performed for all the patients with modified M-shaped genioplasty under general anesthesia according to the preoperative designs. All patients have completed the FACE-Q preoperatively and 3 months postoperatively. The results were evaluated by clinical appearances and FACE-Q scores. RESULTS: The vertical lengthening of the chin was 2-5 mm, with an average of 3.02 mm. The horizontal narrowing width was 3-6 mm, with an average of 5.6 mm. FACE-Q scores in satisfaction with the chin increased significantly from 35.34 ± 9.57 to 72.95 ± 6.81. There were no severe complications took place during the time frame of 3-24 months postoperatively. CONCLUSIONS: The modified M-shaped genioplasty preserved the bone structure in the midsymphyseal area and suprahyoid muscular attachments as far as possible, and the bone segments may be repositioned quickly. This technique produced reliable and esthetically satisfying results in correcting a short, flat and broad chin, with altered vertical length, slope, width and protrusion three-dimensionally. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

A Retrospective Study of Transaxillary Endoscopic Breast Augmentation Using Ultrasonic Scalpel or Conventional Electrocautery for Implant Pocket Dissection.

BACKGROUND: Ultrasonic scalpel has been reported to be superior to conventional electrocautery in many studies. However, with respect to transaxillary endoscopic breast augmentation, few studies on the effect of ultrasonic scalpel are available in the literature. METHODS: The medical records of 173 female patients who underwent breast augmentation via endoscopic transaxillary approach from January 2018 to December 2020 were reviewed retrospectively. The patients were divided into two groups according to the implant pocket dissection instruments. In group A, the implant pockets were dissected with conventional electrocautery (EC group) on 81 patients, and in group B, ultrasonic scalpel (US group) was used for implant pockets on 92 patients. All operations were performed by the same senior plastic surgeon and the same surgical team. The operation time, intraoperative blood loss, postoperative total drainage volume, days of drainage, postoperative surgical site pain and hospital stay time of the two groups were compared and analyzed statistically. RESULTS: The average operation time of the US group (83.82 ± 11.57 min) was significantly shorter than that of the EC group (101.40 ± 14.36 min), intraoperative blood loss in the US group was significantly less than that of the EC group (18.67 ± 6.20 ml vs. 21.59 ± 6.44 ml), the mean hospital stay days (2.96 ± 0.69 vs. 4.30 ± 1.11), total drainage volume (122.24 ± 43.81 vs. 232.37 ± 99.15), and duration of drain (2.52 ± 0.54 vs. 3.77 ± 1.10), mean VAS score for surgical site pain on 3 postoperative days (5.08 ± 1.35 vs. 6.51 ± 1.36, 4.08 ± 1.16 vs. 5.40 ± 1.32, 3.04 ± 0.91 vs. 4.06 ± 1.11) were significantly lower in the US group compared to the EC group. CONCLUSIONS: The ultrasonic scalpel reduces operative time, intraoperative blood loss, postoperative drainage, postoperative pain, hospital stay time, and incidence of complications. The ultrasonic scalpel is safe and reliable for transaxillary endoscopic breast augmentation. LEVEL OF EVIDENCE IV: This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

A nomogram for accurately predicting the surgical site infection following transforaminal lumbar interbody fusion in type 2 diabetes patients, based on glycemic variability.

Surgical site infection (SSI) is a common and serious complication of transforaminal lumbar interbody fusion (TLIF), and the occurrence of SSI usually leads to prolonged hospitalisation, increased medical costs, poor prognosis, and even death. The objectives of this study were to compare the incidence of SSI in patients with type 2 diabetes, investigate the correlation between perioperative glycemic variability and postoperative SSI, and develop a nomogram model to predict the risk of SSI. This study retrospectively analysed 339 patients with type 2 diabetes who underwent TLIF in the spinal surgery department of the Affiliated Zhongda Hospital of Southeast University from January 2018 to September 2021. The medical records of all patients were collected, and postoperative infection cases were determined according to the diagnostic criteria of surgical site infection. The risk factors for postoperative SSI were analysed by univariate and multivariate logistic regression. And Nomogram prediction model was established and validated. The nomogram incorporated seven independent predictors. Preoperative FPG-CV was the most important independent risk predictor of SSI, followed by preoperative MFBG, duration of drain placement, postoperative FPG-CV, preoperative blood glucose control scheme, duration of diabetes >5 years, and the number of fused vertebrae ≥2. The nomogram showed good diagnostic accuracy for the SS of both the training cohort and the validation cohort (AUC = 0.915 and AUC = 0.890). The calibration curves for the two cohorts both showed optimal agreement between nomogram prediction and actual observation. In conclusion, preoperative and postoperative glycemic variability is closely related to the occurrence of SSI. We developed and validated a nomogram to accurately predict the risk of SSI after TLIF surgery. It's helpful for spinal surgeons to formulate reasonable treatment plans and prevention strategies for type 2 diabetes patients.

High-speed Ge-on-GaAs photodetector.

In this work, a germanium (Ge) on gallium arsenide (GaAs) photodetector is demonstrated with the optical response from 850 nm to 1600 nm, which has potential for monolithic integration with VCSELs on GaAs platform as transceiver working beyond 900 nm. The device exhibits a responsivity of 0.35A/W, 0.39 A/W and 0.11 A/W at 1000 nm, 1310 nm and 1550 nm, respectively and dark current of 8 nA at -1 V. The 10 µm diameter back-illuminated device achieves a 3-dB bandwidth of 9.3 GHz under -2 V bias. A donor-like trap at the interface between the Ge and GaAs collection layers is verified by capacitance-voltage curve and deep-level transient spectroscopy (DLTS) measurement, which impedes the depletion in GaAs collection layers.

Resonance-Induced Reduction of Interfacial Tension of Water-Methane and Improvement of Methane Solubility in Water.

Molecular dynamics simulations were performed to study the effect of the periodic oscillating electric field on the interface between water and methane. We propose a new strategy that utilizes oscillating electric fields to reduce the interfacial tension (IFT) between water and methane and increase the solubility of methane in water simultaneously. These are attributed to the hydrogen bond resonance induced by an electric field with a frequency close to the natural frequency of the hydrogen bond. The resonance breaks the hydrogen bond network among water molecules to the maximum, which destroys the hydration shell and reduces the cohesive action of water, thus resulting in the decrease of IFT and the increase of methane solubility. As the frequency of the electric field is close to the optimum resonant frequency of hydrogen bonds, IFT decreases from 56.43 to 5.66 mN/m; water and methane are miscible because the solubility parameter of water reduces from 47.63 to 2.85 MPa1/2, which is close to that of methane (3.43 MPa1/2). Our results provide a new idea for reducing the water-gas IFT and improving the solubility of insoluble gas in water and theoretical guidance in the fields of natural gas exploitation, hydrate generation, and nanobubble nucleation.

Unfolded protein response alleviates acid-induced premature senescence by promoting autophagy in nucleus pulposus cells.

Acid-induced cellular senescence is a critical underlying mechanism of intervertebral disc (IVD) degeneration (IDD). Acid stimulation activates a variety of biological changes including autophagy, endoplasmic reticulum stress, and related unfolded protein response (UPR), which are important regulators of cellular senescence. However, the precise mechanism of acid-mediated UPR and autophagy in nucleus pulposus cell (NPC) senescence has not been fully elucidated. In this study, we used acid to mimic the acidic microenvironment of IVD, and rat NPCs were cultured with or without autophagy or UPR signaling small-interfering RNAs. The related proteins and genes were assessed by immunofluorescence staining assay, Western blot analyses, and quantitative real-time polymerase chain reaction to monitor the activation of these signals and classify the molecular mechanisms underlying the correlation between autophagy and UPR pathway. Cell cycle analyses, senescence-associated ß-galactosidase staining, gene expression, and immunoblotting analyses were performed to observe NPC senescence. Results showed that acid stimulation not only induced NPC senescence, but also initiated UPR and autophagy. Silencing the binding immunoglobulin protein signaling of UPR or autophagy signaling promoted rat NPC senescence. Knock-down of the UPR also blocked NPC autophagy. Taken together, UPR inhibits NPC senescence under acidic condition by activating autophagy. Hence, UPR-dependent autophagy could be an effective biologic target for the treatment of IDD in the future.

Differentiation of lumbar disc herniation and lumbar spinal stenosis using natural language processing-based machine learning based on positive symptoms.

OBJECTIVE: The purpose of this study was to develop natural language processing (NLP)-based machine learning algorithms to automatically differentiate lumbar disc herniation (LDH) and lumbar spinal stenosis (LSS) based on positive symptoms in free-text admission notes. The secondary purpose was to compare the performance of the deep learning algorithm with the ensemble model on the current task. METHODS: In total, 1921 patients whose principal diagnosis was LDH or LSS between June 2013 and June 2020 at Zhongda Hospital, affiliated with Southeast University, were retrospectively analyzed. The data set was randomly divided into a training set and testing set at a 7:3 ratio. Long Short-Term Memory (LSTM) and extreme gradient boosting (XGBoost) models were developed in this study. NLP algorithms were assessed on the testing set by the following metrics: receiver operating characteristic (ROC) curve, area under the curve (AUC), accuracy score, recall score, F1 score, and precision score. RESULTS: In the testing set, the LSTM model achieved an AUC of 0.8487, accuracy score of 0.7818, recall score of 0.9045, F1 score of 0.8108, and precision score of 0.7347. In comparison, the XGBoost model achieved an AUC of 0.7565, accuracy score of 0.6961, recall score of 0.7387, F1 score of 0.7153, and precision score of 0.6934. CONCLUSIONS: NLP-based machine learning algorithms were a promising auxiliary to the electronic health record in spine disease diagnosis. LSTM, the deep learning model, showed better capacity compared with the widely used ensemble model, XGBoost, in differentiation of LDH and LSS using positive symptoms. This study presents a proof of concept for the application of NLP in prediagnosis of spine disease.

The Accuracy of a Patient-Specific Three-Dimensional Digital Ostectomy Template for Mandibular Angle Ostectomy.

BACKGROUND: Although three-dimensional (3D)-printed digital ostectomy templates (DOTs) can help surgeons perform mandibular angle ostectomy (MAO) more precisely and safely, the clinical application of such templates is problematic. OBJECTIVES: The aim of this study was to evaluate the accuracy of a novel DOT and improve the precision of MAO. METHODS: A total of 20 patients with a prominent mandibular angle (PMA) were allocated into 2 groups (10 patients per group). A conventional DOT and a novel DOT were applied to guide MAO in Groups A and B, respectively. The mean time taken for curved osteotomy and the volume of postoperative drainage on 1 side within 24 hours were recorded. The deviations between the simulated and postoperative lower border of the mandible were measured on both sides. RESULTS: All the patients were satisfied with the cosmetic outcomes. Statistical results showed that the mean time taken for curved osteotomy was shorter in Group B than in Group A, and that the volume of postoperative drainage on 1 side within 24 hours was similar between the 2 groups. The deviations at the anterior and posterior parts of the inferior border showed that the accuracy of osteotomy was higher in Group B than in Group A, and that there was no significant difference between the 2 groups in the middle part. CONCLUSIONS: The novel DOT is easy to locate and fix tightly, which reduced the operating time and increased the safety and precision of the procedures.

Characteristics of thin InAlAs digital alloy avalanche photodiodes.

InP-based avalanche photodiodes (APDs) are widely used in short-wave infrared (SWIR) communications. In this work, a thin (200 nm nominal) InAlAs digital alloy layer consisting of two monolayer (ML) InAs and two ML AlAs was grown on InP substrate and investigated in detail. APDs with p-i-n and n-i-p structures were fabricated and characterized. The current-voltage, capacitance-voltage characteristics, and excess noise were measured at room temperature with different laser wavelengths, and the measured effective k value (ratio of impact ionization coefficients) is about 0.15 with the multiplication gain up to 12. The randomly-generated path length (RPL) model was carried out to analyze the dead space effect. Our thin digital alloy successfully reduced excess noise compared with conventional In0.52Al0.48As random alloy without introducing new elements and shows the potential for high-speed, low noise APD applications.

Electronic characteristics of BRCA1 mutations in DNA.

The efficient and low-cost way for gene mutation detection and identification are conducive for the detection of disease. Here, we report the electronic characteristics of the gene of breast cancer 1 in four common mutation types: duplication, single nucleotide variant, deletion, and indel. The electronic characteristics are investigated by the combination of density functional theory and non-equilibrium Green's function formulation with decoherence. The magnitude of conductance of these DNA molecules and mutational changes are found to be detectable experimentally. In this study, we also find the significant mutation type dependent on the change of conductance. Hence these mutations are expected to be identifiable. We find deletion type mutation shows the largest change in relative conductance (~97%), whereas the indel mutation shows the smallest change in relative conductance (~27%). Therefore, this work presents a possibility of electronic detection and identification of mutations in DNA, which could be an efficient method as compared to the conventional methods.

High-speed mid-wave infrared interband cascade photodetector at room temperature.

High-speed mid-wave infrared (MWIR) photodetectors have important applications in the emerging areas such high-precision frequency comb spectroscopy and light detection and ranging (LIDAR). In this work, we report a high-speed room-temperature mid-wave infrared interband cascade photodetector based on a type-II InAs/GaSb superlattice. The devices show an optical cut-off wavelength around 5 µm and a 3-dB bandwidth up to 7.04 GHz. The relatively low dark current density around 9.39 × 10-2 A/cm2 under -0.1 V is also demonstrated at 300 K. These results validate the advantages of ICIPs to achieve both high-frequency operation and low noise at room temperature. Limitations on the high-speed performance of the detector are also discussed based on the S-parameter analysis and other RF performance measurement.

Protein kinase RNA-like ER kinase/eukaryotic translation initiation factor 2α pathway attenuates tumor necrosis factor alpha-induced apoptosis in nucleus pulposus cells by activating autophagy.

Cellular loss induced by tumor necrosis factor alpha (TNF-α) contributes to the pathogenesis of intervertebral disc (IVD) degeneration. Cellular stress induced by TNF-α activates several processes to restore cell homeostasis. These processes include autophagy, endoplasmic reticulum stress, and related unfolded protein response (UPR). However, the effect and mechanism of UPR and autophagy regulated by TNF-α in IVD degeneration (IDD) remain unclear. The effect of autophagy on biological changes in nucleus pulposus cells (NPCs) also remains elusive. In this study, rat NPCs were cultured with TNF-α in the presence or absence of the UPR or autophagy pathway small-interfering RNAs. The associated genes and proteins were evaluated through immunofluorescence staining, quantitative real-time polymerase chain reaction (qRT-PCR) and western blot analyses to monitor UPR and autophagy signaling and identify the regulatory mechanism of autophagy by the UPR pathway. Trypan blue exclusion assay, cell flow cytometry, terminal deoxynucleotidyl transferase dUTP nick end labeling staining, qRT-PCR, and western blot analyses were performed to examine the apoptosis of NPCs. The results showed that the acute exposure of TNF-α induced the apoptosis of rat NPCs and activated the protein kinase RNA-like ER kinase/eukaryotic translation initiation factor 2α (PERK/eIF2α) pathway of UPR and initiated autophagy. Silencing the PERK/eIF2α pathway or inhibiting autophagy enhanced the apoptosis of NPCs. Interference of the PERK/eIF2α pathway suppressed the autophagy of rat NPCs under TNF-α stimulation. Taken together, the PERK/eIF2α pathway reinforces the survival of NPCs under TNF-α stimulation by activating autophagy. Therefore, PERK/eIF2α-dependent autophagy could be a novel biological therapeutic target for IDD.

A histocytological and radiological overview of the natural history of intervertebral disk: from embryonic formation to age-related degeneration.

PURPOSE: To elucidate the natural history of intervertebral disk (IVD) and characterize its embryonic beginnings and age-related degeneration. METHODS: Coronal sections of embryonic (E13.5-neonatal) and postnatal (4-60-week-old) Sprague-Dawley rat IVD were stained by a series of histological stainings (hematoxylin and eosin, Alcian blue, Picrosirius red, Masson, Periodic acid-Schiff). Growth kinetics within embryonic IVD were evaluated by immunohistochemical staining of Ki67 and proliferating cell nuclear antigen. Postnatal maturation and degeneration of IVD were visualized on radiology by X-ray, CT, and MR imaging. RESULTS: During the formation of rat IVD, inner annulus fibrosus (AF) and cartilaginous endplate (CEP) shared similar cell density, extracellular matrix, and potential of growth kinetics; notochord provided increased and enlarged cytoplasmic vacuoles to generate nucleus pulposus (NP), part of which was retained within CEP. Postnatally, vacuolated notochord cells were reduced by devacuolation, while chondrocytic NP cells increased; cartilaginous layers of CEP were narrowed by vertebrae growth and secondary ossification; fibrotic portion of AF decreased as cartilaginous matrix accumulated and infiltrated outward. In aged and degenerated IVD, large longitudinal fissures were detected near the boundaries between inner and outer AF, whereas both reduced cellularity and accumulated cell clusters were evident within the dehydrated NP; only part of these histocytological changes could be reported on radiology. CONCLUSIONS: By showing that the natural history of IVD is orchestrated by a dynamic histocytological regulation, our study may facilitate better understanding of the developmental defects, cellular heterogeneity, age-related degenerative mechanisms, and biological regeneration of IVD. These slides can be retrieved under Electronic Supplementary Material.

Comparison of percutaneous endoscopic lumbar discectomy versus microendoscopic discectomy for the treatment of lumbar disc herniation: a meta-analysis.

PURPOSE: We conducted a systematic review and meta-analysis to compare the clinical outcomes of percutaneous endoscopic lumbar discectomy (PELD) and microendoscopic discectomy (MED) for the treatment of lumbar disc herniation (LDH), and to clarify whether PELD is more superior to MED. METHODS: We performed a comprehensive search in the databases of MEDLINE, EMBASE, PubMed, Web of Science, Cochrane database, CNKI, and Wanfang Data to acquire all relevant studies up to July 2018. The searched literatures were then screened according to the strict inclusion and exclusion criteria. The critical data were extracted and analyzed utilizing Review Manager software. The pooled effects were calculated by mean difference (MD) or odds ratio (OR) with 95% confidence intervals (CI) on the basis of data attributes. RESULTS: A total of 18 studies (2161 patients, 1093 in the PELD group and 1068 in the MED group) were included in this systematic review and meta-analysis. At last follow-up, the results revealed that no significant difference was found between PELD group and MED group with respect to ODI (MD - 0.30; 95% CI - 1.02 to 0.42; P = 0.41), VAS-leg pain (MD - 0.18; 95% CI - 0.45 to 0.09; P = 0.19), VAS-unspecified (MD - 0.00; 95% CI - 0.05 to 0.04; P = 0.94), excellent & good rate (OR, 1.04; 95% CI 0.68 to 1.59; P = 0.86), total complication rate (OR, 0.96; 95% CI 0.65 to 1.43; P = 0.85), dural tear rate (OR, 0.39; 95% CI 0.10 to 1.55; P = 0.18), and residue or recurrence rate (OR, 2.22; 95% CI 1.02 to 4.83; P = 0.05). When compared to MED group, the PELD group showed significantly better results with regard to shorter length of incision (MD - 1.18; 95% CI - 1.39 to - 0.97; P < 0.00001), less blood loss (MD - 45.17; 95% CI - 64.74 to - 25.60; P < 0.00001), shorter post-operative in-bed time (MD - 59.11; 95% CI - 71.19 to - 47.04; P < 0.00001), shorter post-operative hospital stay (MD - 3.07; 95% CI - 4.81 to - 1.33; P < 0.00001), shorter total hospital stay (MD - 2.29; 95% CI - 3.03 to - 1.55; P < 0.00001), and lower VAS-back pain at last follow-up (MD - 0.77; 95% CI - 1.31 to - 0.24; P = 0.005), but with significantly worse results such as more fluoroscopy (MD 7.63; 95% CI 5.25 to 10.01; P < 0.00001) and higher re-operation rate (OR, 2.67; 95% CI 1.07 to 6.67; P = 0.04). Although no significant difference was found between the two groups in terms of duration of operation (MD 6.27; 95% CI - 2.44 to 14.98; P = 0.16) and total hospital cost (MD - 0.69; 95% CI - 12.60 to 11.23; P = 0.91), further subgroup analysis revealed that the duration of operation was significantly longer in the PELD group compared with the MED group in "Years before 2016" (MD 24.97; 95% CI 7.07 to 42.87; P = 0.006) and "Year 2016 to 2017" (MD 6.57; 95% CI 0.58 to 12.55; P = 0.03) subgroups but not in the subgroup "Year 2018" (MD - 5.66; 95% CI - 18.84 to 7.53; P = 0.40), and that the total hospital cost was significantly more in the PELD group compared with the MED group in the subgroup "Southeast of China" (MD 6.67; 95% CI 3.23 to 10.28; P = 0.0002) but not in the subgroup "Midwest of China" (MD - 8.09; 95% CI - 17.99 to 1.80; P = 0.11). CONCLUSIONS: For the treatment of LDH, both of PELD and MED can reach excellent results and no superiority was found between the two minimally invasive procedures with regard to duration of operation, ODI, VAS-leg pain, VAS-unspecified, excellent & good rate, total complication rate, dural tear rate, and residue or recurrence rate. While PELD can achieve better outcomes with respect to the length of incision, blood loss, post-operative in-bed time, post-operative hospital stay, total hospital stay, and VAS-back pain at last follow-up, however, MED showed certain advantages of less fluoroscopic times and lower re-operation rate. More practice and development are needed to make up for the deficiencies of PELD. Besides, the economic factor should also be considered according to different regions before making the treatment strategies. Well-defined randomized controlled trials with large samples are needed to further confirm these results.