SARS-CoV-2 reinfection broadens the antibody responses and promotes the phenotypic differentiation of virus-specific memory T cells in adolescents.

The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron subvariants raises concerns regarding the effectiveness of immunity acquired from previous Omicron subvariants breakthrough infections (BTIs) or reinfections (RIs) against the current circulating Omicron subvariants. In this study, we prospectively investigate the dynamic changes of virus-specific antibody and T cell responses among 77 adolescents following Omicron BA.2.3 BTI with or without subsequent Omicron BA.5 RI. Notably, the neutralizing antibodies (NAbs) titers against various detected SARS-CoV-2 variants, especially the emerging Omicron CH.1.1, XBB.1.5, XBB.1.16, EG.5.1, and JN.1 subvariants, exhibited a significant decrease along the time. A lower level of IgG and NAbs titers post-BTI was found to be closely associated with subsequent RI. Elevated NAbs levels and shortened antigenic distances were observed following Omicron BA.5 RI. Robust T cell responses against both Omicron BA.2- and CH.1.1-spike peptides were observed at each point visited. The exposure to Omicron BA.5 promoted phenotypic differentiation of virus-specific memory T cells, even among the non-seroconversion adolescents. Therefore, updated vaccines are needed to provide effective protection against newly emerging SARS-CoV-2 variants among adolescents.

Humoral and cellular immune responses following Omicron BA.2.2 breakthrough infection and Omicron BA.5 reinfection.

The emergence of novel Omicron subvariants has raised concerns regarding the efficacy of immunity induced by prior Omicron subvariants breakthrough infection (BTI) or reinfection against current circulating Omicron subvariants. Here, we prospectively investigated the durability of antibody and T cell responses in individuals post Omicron BA.2.2 BTI, with or without subsequent Omicron BA.5 reinfection. Our findings reveal that the emerging Omicron subvariants, including CH.1.1, XBB, and JN.1, exhibit extensive immune evasion induced by previous infections. Notably, the level of IgG and neutralizing antibodies were found to correlate with subsequent Omicron BA.5 reinfection. Fortunately, T cell responses recognizing both Omicron BA.2 and CH.1.1 peptides were observed. Furthermore, Omicron BA.5 reinfection may alleviate immune imprinting induced by WT-vaccination, bolster virus-specific ICS+ T cell responses, and promote the phenotypic differentiation of virus-specific memory CD8+ T cells. Antigen-updated or T cell-conserved vaccines are needed to control the transmission of diverse emerging SARS-CoV-2 variants.

Impact of antifibrotic therapy on disease progression, all-cause mortality, and risk of acute exacerbation in non-IPF fibrosing interstitial lung diseases: evidence from a meta-analysis of randomized controlled trials and prospective controlled studies.

BACKGROUND: Nintedanib and pirfenidone are preferred pharmacological therapies for patients with idiopathic pulmonary fibrosis (IPF). However, evidence favoring antifibrotic therapy in patients with non-IPF fibrosing interstitial lung diseases (ILD) is limited. OBJECTIVE: To investigate the effects of antifibrotic therapy on disease progression, all-cause mortality, and acute exacerbation (AE) risk in patients with non-IPF fibrosing ILDs. DESIGN: Meta-analysis. DATA SOURCES AND METHODS: Electronic databases were searched for articles published before 28 February 2023. Studies that evaluated the efficacy of antifibrotic agents in patients with fibrosing ILDs were selected. The primary outcome was the disease progression risk, and the secondary outcomes included all-cause mortality and AE risk. The GRADE criteria were used for the certainty of evidence assessment. RESULTS: Nine studies with 1990 participants were included. Antifibrotic therapy reduced the rate of patients with disease progression (five trials with 1741 subjects; relative risk (RR), 0.56; 95% CI, 0.42-0.75; p < 0.0001; I2 = 0; high-certainty evidence). Antifibrotic therapy did not significantly decrease all-cause mortality (nine trials with 1990 subjects; RR, 0.76; 95% CI, 0.55-1.03; p = 0.08; I2 = 0; low-certainty evidence). However, in patients with progressive fibrosing ILDs (PF-ILD), antifibrotic therapy decreased all-cause mortality (four trials with 1100 subjects; RR, 0.69; 95% CI, 0.48-0.98; p = 0.04; I2 = 0; low-certainty evidence). CONCLUSION: Our study supports the use of antifibrotic agents in patients with PF-ILDs, which could slow disease progression and decrease all-cause mortality. TRIAL REGISTRATION: This study protocol was registered with PROSPERO (registration number: CRD42023411272).

Zika virus targets human trophoblast stem cells and prevents syncytialization in placental trophoblast organoids.

Zika virus (ZIKV) infection during pregnancy threatens pregnancy and fetal health. However, the infectivity and pathological effects of ZIKV on placental trophoblast progenitor cells in early human embryos remain largely unknown. Here, using human trophoblast stem cells (hTSCs), we demonstrated that hTSCs were permissive to ZIKV infection, and resistance to ZIKV increased with hTSC differentiation. Combining gene knockout and transcriptome analysis, we demonstrated that the intrinsic expression of AXL and TIM-1, and the absence of potent interferon (IFN)-stimulated genes (ISGs) and IFNs contributed to the high sensitivity of hTSCs to ZIKV. Furthermore, using our newly developed hTSC-derived trophoblast organoid (hTSC-organoid), we demonstrated that ZIKV infection disrupted the structure of mature hTSC-organoids and inhibited syncytialization. Single-cell RNA sequencing (scRNA-seq) further demonstrated that ZIKV infection of hTSC-organoids disrupted the stemness of hTSCs and the proliferation of cytotrophoblast cells (CTBs) and probably led to a preeclampsia (PE) phenotype. Overall, our results clearly demonstrate that hTSCs represent the major target cells of ZIKV, and a reduced syncytialization may result from ZIKV infection of early developing placenta. These findings deepen our understanding of the characteristics and consequences of ZIKV infection of hTSCs in early human embryos.

Rational design of genotyping nanodevice for HPV subtype distinction.

There are more than 200 subtypes of human papillomavirus (HPV), and high-risk HPVs are a leading cause of cervical cancer. Identifying the genotypes of HPV is significant for clinical diagnosis and cancer control. Herein, we used programmable and modified DNA as the backbone to construct fluorescent genotyping nanodevice for HPV subtype distinction. In our strategy, the dye-labeled single-stranded recognize-DNA (R-DNA) was hybridized with Black Hole Quencher (BHQ) labeled single-stranded link-DNA (L-DNA) to form three functionalized DNA (RL-DNA). Through the extension of polycytosine (poly-C) in L-DNA, three RL-DNAs can be more firmly adsorbed on graphene oxide to construct reliable genotyping nanodevice. The genotyping nanodevice had low background noise since the dual energy transfer, including Förster resonance energy transfer (FRET) from dye to BHQ and the resonance energy transfer (RET) from dye to graphene oxide. Meanwhile, the programmability of DNA allows the proposed strategy to simultaneously and selectively distinguish several HPV subtypes in solution using DNA labeled with different dyes. To demonstrate clinical potential, we show multiplexed assay of HPV subtypes in cervical scrapes, and it has been successfully applied in HPV-DNA analysis in cervical scrapes samples. The genotyping nanodevice could be developed for simultaneous and multiplex analysis of several oligonucleotides in a homogeneous solution by adjusting the recognition sequence, demonstrating its potential application in the rapid screening of multiple biomarkers.

Aberrant intra- and internetwork functional connectivity patterns of the anterior and posterior hippocampal networks in schizophrenia.

AIM: Schizophrenia is associated with abnormal hippocampal structure and function. Available evidence suggests that the anterior and posterior hippocampus are differentially affected by schizophrenia pathology. This study was designed to provide new insight into the anterior and posterior hippocampus in schizophrenia from the perspective of functional connectivity. METHODS: Based on resting-state functional magnetic resonance imaging data of 71 schizophrenia patients and 74 normal controls, we utilized a data-driven approach to functionally segment the hippocampus into anterior and posterior segments and then investigated the functional connectivity patterns within and between the two hippocampal networks at the network, edge, and nodal levels. RESULTS: We found that schizophrenia patients showed hyperconnectivity of both the anterior and posterior hippocampal networks. We also observed that the network alterations appear somewhat greater in the anterior hippocampal network than the posterior network, the left side than the right, and the intranetwork connectivity than the internetwork connectivity. CONCLUSION: The results reveal convergent and divergent intranetwork and internetwork connectivity patterns of the anterior and posterior hippocampus in schizophrenia, providing novel and important insights into the mechanisms of hippocampal pathology in schizophrenia.

Effect of metformin use on the risk and prognosis of ovarian cancer: an updated systematic review and meta-analysis.

INTRODUCTION: Emerging evidence suggests that metformin has a potential antitumor effect both in vitro and in vivo. Increasing epidemiological studies indicate that diabetic patients receiving metformin therapy have lower incidences of cancer and have better survival rates. However, there are limited and inconsistent studies available about the effect of metformin therapy on ovarian cancer (OC). Thus, we conducted this meta-analysis to study the effect of metformin therapy on OC. Meanwhile, we systematically reviewed relevant studies to provide a framework for future research. EVIDENCE ACQUISITION: We conducted a systematic literature search on PubMed, Web of Science, Springerlink, CNKI, VIP, SinoMed, and Wanfang up to the period of October 2018. A random-effects meta-analysis model was used to derive pooled effect estimates. EVIDENCE SYNTHESIS: A total of 13 studies were retrieved of which 5 studies explained the prevention and 8 studies explained the treatment for OC. Our pooled results showed that metformin has a potential preventive effect on OC in diabetic women (pooled odds ratio [OR] 0.62, 95% confidence interval [95% CI] 0.34, 1.11; P<0.001). In addition, metformin can also significantly prolong progression-free survival (PFS) (pooled hazard ratio [HR] 0.49, 95% CI 0.34, 0.70; P=0.002), and overall survival (OS) (HR 0.71, 95%CI 0.61, 0.82; P<0.001) in patients with OC, regardless of whether they had diabetes. CONCLUSIONS: The use of metformin can potentially reduce the risk of OC among diabetics, and it also can significantly improve PFS and OS in patients with OC. A further large clinical investigation would be needed to adopt our finding in practice, however, our systematic review provides an insight for future study designs.

Baicalin attenuates adriamycin-induced nephrotic syndrome by regulating fibrosis procession and inflammatory reaction.

BACKGROUND: Baicalin has anti-inflammatory, antibacterial, blood platelet aggregation-inhibiting, free oxygen radical-clearing, and endotoxin-decreasing properties. However, its molecular mechanism involved in the treatment of Adriamycin-induced nephrotic syndrome (NS) is still unclear. OBJECTIVE: This study aimed to explore the effects of baicalin on Adriamycin-induced nephrotic syndrome (NS) and to characterize the genes involved in this progression. METHODS: We established Adriamycin-induced NS model in 32 rats and used six rats in Sham group. Urinary total protein content and creatinine serum were assessed as physiological indicators. H&E staining was used to observe the pathological changes. We determined gene expression profiles using transcriptome sequencing in the rat kidney tissues from Sham, Adriamycin, and Adriamycin + baicalin groups. KEGG was carried out to analyze the enriched pathways of differentially expressed genes among these groups. RESULTS: Baicalin treatment relieved renal injury in NS rats. Expression of 363 genes was significantly different between the Adriamycin and Adriamycin + baicalin M groups. Most of the differentially expressed genes were enriched in pathways involved in epithelial-mesenchymal transition (EMT), fibrosis, apoptosis, and inflammation. CONCLUSIONS: Overall, these data suggest that Adriamycin-induced NS can be attenuated by baicalin through the suppression of fibrosis-related genes and inflammatory reactions. Baicalin is a potential drug candidate for the treatment of NS, and the identified genes represent potential therapeutic targets.

Oridonin suppresses autophagy and survival in rheumatoid arthritis fibroblast-like synoviocytes.

Context: Oridonin exhibits various pharmacological and physiological activities, including antioxidant, antibacterial, anti-inflammatory, pro-apoptotic, anticancer and neurological effects. However, its role in rheumatoid arthritis (RA) is yet to be revealed.Objective: We evaluated the effects of oridonin on the survival and autophagy of RA-fibroblast-like synoviocytes (FLSs).Materials and methods: RA-FLSs were treated with oridonin at serial concentrations of 0, 2, 4, 6, 8 and 10 µg/mL for 24, 48 and 72 h. Then, cell proliferation and apoptosis were measured. A GFP-LC3 plasmid was transfected into the cells to determine autophagy.Results: Oridonin suppressed RA-FLS proliferation in a dose-dependent manner. The half maximal inhibitory concentrations (IC50) of oridonin at 24, 48 and 72 h were 8.28, 7.88 and 8.35 µg/mL, respectively. Treatment with oridonin for 24 h increased apoptosis by 4.1%, and increased the protein levels of Bax and cleaved caspase-3 but significantly decreased the levels of IL-1ß in the culture supernatant (p < 0.05). In addition, 6 h of oridonin treatment significantly decreased the number of GFP-LC3 punctate dots and inhibited the protein levels of ATG5 and Beclin1 by 80.01% and 42.12%, respectively. Chloroquine (CQ) significantly reinforced the effects of oridonin on inhibition of autophagy, suppression of proliferation, and induction of apoptosis in RA-FLSs (p < 0.05).Conclusions: Our results indicate that treatment with oridonin in combination with CQ inhibits autophagy and cell proliferation and induces apoptosis in RA-FLSs more effectively than treatment oridonin alone. This finding indicates that oridonin is a potential therapeutic agent for RA.

Polarity-Sensitive Polymer Carbon Dots Prepared at Room-Temperature for Monitoring the Cell Polarity Dynamics during Autophagy.

Taking the advantages of excellent optical properties, biocompatibility, and photostability of carbon dots, herein, we developed polarity-sensitive polymer carbon dots (PCDs) for visualizing of cellular polarity to real-time monitoring autophagy changes without perturbing the cellular status. The PCDs can be prepared by simply mixing dopamine (DA), H2O2, and o-phenylenediamine (o-PDA) in a common beaker without the need for any special equipment or external energy supply, and the preparation could be completed within 3 min at room temperature. Interestingly, the polarity-sensitive PCDs could emit various types of fluorescence and are insensitive to the excitation light when dispersed in different water/dioxane systems with different polarities. Based on the polarity-sensitive emission of the PCDs, the change of polarity during autophagy has been successfully monitored in living cells. Moreover, the change of polarity detected by PCDs is autophagy-specific (does not occur during apoptosis), occurs under different autophagy-inducing situations (starvation, rapamycin, and trehalose), and requires a normal autophagic flux, showing that PCDs rapidly prepared by polymerization cross-linking at room temperature can be functionally applied in the case of autophagy-related physiological or pathological processes.

Treatment with Melittin Induces Apoptosis and Autophagy of Fibroblastlike Synoviocytes in Patients with Rheumatoid Arthritis.

BACKGROUND: Melittin, the major medicinal component of honeybee venom, exerts antiinflammatory, analgesic, and anti-arthritic effects in patients with Rheumatoid Arthritis (RA). RA is an inflammatory autoimmune joint disease that leads to irreversible joint destruction and functional loss. Fibroblast-Like Synoviocytes (FLS) are dominant, special mesenchymal cells characterized by the structure of the synovial intima, playing a crucial role in both the initiation and progression of RA. OBJECTIVE: In this study, we evaluated the effects of melittin on the viability and apoptosis of FLS isolated from patients with RA. METHODS: Cell viability was determined using CCK-8 assays; apoptosis was evaluated by flow cytometry, and the expression levels of apoptosis-related proteins (caspase-3, caspase-9, BAX, and Bcl-2) were also determined. To explore whether melittin alters inflammatory processes in RA-FLS, IL-1ß levels were determined using an enzyme-linked immunosorbent assay (ELISA). Furthermore, we performed GFP-LC3 punctate fluorescence dot assays and western blotting (for LC3, ATG5, p62, and Beclin 1) to assess autophagy in RA-FLS. RESULTS: Our results show that melittin can significantly impair viability, promote apoptosis and autophagy, and inhibit IL-1ß secretion in RA-FLS. CONCLUSION: Melittin may be useful in preventing damage to the joints during accidental local stimulation.

MiR-26a-5p Inhibits Cell Proliferation and Enhances Doxorubicin Sensitivity in HCC Cells via Targeting AURKA.

OBJECTIVE: To investigate the role of miR-26a-5p in cell proliferation and doxorubicin sensitivity in hepatocellular carcinoma. METHODS: We evaluated miR-26a-5p expression in hepatocellular carcinoma tissues and cell lines by reverse transcription polymerase chain reaction. Cell Counting Kit-8 was used to examine cell proliferation. Relationship between miR-26a-5p and aurora kinase A was evaluated by luciferase report system. Western blot was used to detect expression of aurora kinase A. RESULTS: In this study, we observed miR-26a-5p was downregulated in hepatocellular carcinoma tissues and cell lines. Gain-of-function experiments showed that proliferation rate of hepatocellular carcinoma cells decreased under condition of miR-26a-5p mimics. We found miR-26a-5p mimics could enhance doxorubicin sensitivity of hepatocellular carcinoma cells. Further study showed that aurora kinase A was target gene of miR-26a-5p. Suppression of aurora kinase A could lead to lower cell proliferation and higher doxorubicin sensitivity of hepatocellular carcinoma cells. CONCLUSION: Our study found that miR-26a-5p could inhibit cell proliferation and enhance doxorubicin sensitivity in hepatocellular carcinoma cells by targeting aurora kinase A.

Quantitative Analysis of Ultrasound Tissue Diffusion Elastography in The Diagnosis of Benign and Malignant Prostate Lesions.

PURPOSE: This study aims to evaluate the value of quantitative analysis of ultrasound real-time tissue diffusion elastography in the diagnosis of benign and malignant prostate lesions. MATERIALS AND METHODS: From March 2010 to June 2013, 52 patients suspected with prostate cancer based on laboratory or clinical test results and underwent prostate biopsy in our hospital were enrolled into this study. The age of these patients ranged between 45-82 years, with an average age of 67.2 ± 6.8 years. All patients underwent transrectal real-time ultrasound elastography (TRTE) before biopsy. A total of 63 prostate nodules were detected, and the 11 elastic characteristic quantities of these nodules were quantitatively analyzed via tissue diffusion quantitative analysis. The results of ultrasonography were compared with the results of operation and pathology. RESULT: Among these 11 characteristic quantities, which include the mean (MEAN) and standard deviation (SD), blue area ratio (AREA%), complexity (COMP), kurtosis (KURT), skewness (SKEW), contrast (CONT), equality (ENT), entropy (IDM), consistency (ASM) and correlation (CORR), except for COMP and CORR, the differences in other nine characteristic quantities between benign and malignant prostatic nodules were statistically significant (P<0.05). Among these, the AREA% and MEAN had the highest correlation, which were 0.791 and -0.791, respectively. The Youden's index (sensitivity and specificity) of AREA% in the ROC curves was the highest, the cutoff value was 80.65% for the diagnosis of prostate cancer, sensitivity was 87.9%, and specificity was 96.6%. CONCLUSION: Quantitative analysis of ultrasound real-time tissue diffusion elastography is helpful in the diagnosis of benign and malignant prostate lesions, provides a relatively accurate evaluation method in clinical practice, and has broad application prospects.

SHCBP1 is a novel target and exhibits tumor­promoting effects in gastric cancer.

The present study investigated the expression and potential influence of SHC SH2 domain­binding protein 1 (SHCBP1) in gastric cancer (GC) cells. SHCBP1 is closely related to cell proliferation and cell cycle progression, but its role in GC remains unclear. The TCGA database revealed that SHCBP1 is highly expressed in GC tissues. Furthermore, SHCBP1 was revealed to be highly expressed in GC cell lines MGC­803 and SGC­7901 cells, and downregulation of SHCBP1 significantly inhibited GC cell proliferation. Furthermore, SHCBP1 expression promoted cell cycle progression and inhibition of apoptosis. Since the CDK4, cyclin D1 and caspase family proteins play important roles in cell cycle and apoptosis regulation, it was examined whether there was an association between SHCBP1 and these signaling pathways in GC. Our results revealed that SHCBP1 promoted cell cycle progression by regulating the CDK4­cyclin D1 cascade and suppressed caspase­3, caspase PARP­dependent apoptotic pathways. Cell invasion and metastasis experiments also revealed that SHCBP1 promoted tumor growth and invasiveness. These tumor­promoting functions of SHCBP1 may provide a potential molecular basis for the diagnosis and targeted therapy of GC.

Laparoscopic Liver Resection can be an Effective Way in Obese Patients: A Single Center of 2-Year Experience.

OBJECTIVE: To evaluate the feasibility and safety of laparoscopic liver resection in obese patients, we compared the operative outcomes between obese and nonobese patients, also between laparoscopic liver resection and open liver resection of obese and nonobese patients. MATERIALS AND METHODS: A total of 86 patients suffering from liver resection in our department from January 2013 to December 2014 were divided into 3 groups: the obese patients group for laparoscopic liver resection, the nonobese patients group for laparoscopic liver resection and the obese patients group for open liver resection. Characteristics and clinic data of 3 groups were studied. RESULTS: Characteristics of patients and clinic data were equivalent between the 3 groups. The groups were well matched in age, sex distribution, and liver function (P>0.05). There were no significant differences in the operative time, estimated blood loss, time to oral intake, and postoperative hospital stay in the 3 groups. Tumor diameter of laparoscopic liver resection groups in obese patients was smaller than open liver resections groups in obese patients (P<0.05), but there were no obvious difference of tumor diameter in the laparoscopic liver resection groups of the obese patients and the nonobese patients. CONCLUSIONS: Obesity should not be seen as a contraindication for laparoscopic liver resection, which is a safe and feasible procedure for obese patients.

Laparoscopic Versus Open Resection for Liver Cavernous Hemangioma: A Single Center of 2-Year Experience.

OBJECTIVE: To evaluate the feasibility and safety of laparoscopic versus open resection for liver cavernous hemangioma (LCH). MATERIALS AND METHODS: A total of 131 patients suffering from LCH operated in our department between January 2013 and December 2014 were divided into 2 groups: 31 for laparoscopic liver resection (LR) and 100 for open liver resection (OR). RESULTS: Age, sex, presence or absence of chronic liver disease, tumor size, tumor location, type of resection, estimated intraoperative blood loss, operative time, length of postoperative hospital stay, morbidity, and mortality were equivalent between the 2 groups. There were no significant differences in estimated intraoperative blood loss between the LR and OR groups. The operation time of the LR group was longer than the OR group and the hospitalization expenses less than the OR group. However, the time of postoperative hospital stay and time of oral intake were shorter in the LR group than the OR group. The tumor of the LR group was smaller than the OR group. In liver function, alanine aminotransferase after operation of the LR group was lower than the OR group, the same as aspartate transaminase after operation. But there were no significant differences in total bilirubin after operation. CONCLUSIONS: Laparoscopic resection for LCH is a safe and feasible procedure as OR.

Local manifold learning for multiatlas segmentation: application to hippocampal segmentation in healthy population and Alzheimer's disease.

AIMS: Automated hippocampal segmentation is an important issue in many neuroscience studies. METHODS: We presented and evaluated a novel segmentation method that utilized a manifold learning technique under the multiatlas-based segmentation scenario. A manifold representation of local patches for each voxel was achieved by applying an Isomap algorithm, which can then be used to obtain spatially local weights of atlases for label fusion. The obtained atlas weights potentially depended on all pairwise similarities of the population, which is in contrast to most existing label fusion methods that only rely on similarities between the target image and the atlases. The performance of the proposed method was evaluated for hippocampal segmentation and compared with two representative local weighted label fusion methods, that is, local majority voting and local weighted inverse distance voting, on an in-house dataset of 28 healthy adolescents (age range: 10-17 years) and two ADNI datasets of 100 participants (age range: 60-89 years). We also implemented hippocampal volumetric analysis and evaluated segmentation performance using atlases from a different dataset. RESULTS: The median Dice similarities obtained by our proposed method were approximately 0.90 for healthy subjects and above 0.88 for two mixed diagnostic groups of ADNI subjects. CONCLUSION: The experimental results demonstrated that the proposed method could obtain consistent and significant improvements over label fusion strategies that are implemented in the original space.

Load rate of facet joints at the adjacent segment increased after fusion.

BACKGROUND: The cause of the adjacent segment degeneration (ASD) after fusion remains unknown. It is reported that adjacent facet joint stresses increase after anterior cervical discectomy and fusion. This increase of stress rate may lead to tissue injury. Thus far, the load rate of the adjacent segment facet joint after fusion remains unclear. METHODS: Six C2-C7 cadaveric spine specimens were loaded under four motion modes: Flexion, extension, rotation, and lateral bending, with a pure moment using a 6° robot arm combined with an optical motion analysis system. The Tecscan pressure test system was used for testing facet joint pressure. RESULTS: The contact mode of the facet joints and distributions of the force center during different motions were recorded. The adjacent segment facet joint forces increased faster after fusion, compared with intact conditions. While the magnitude of pressures increased, there was no difference in distribution modes before and after fusion. No pressures were detected during flexion. The average growth velocity during extension was the fastest and was significantly faster than lateral bending. CONCLUSIONS: One of the reasons for cartilage injury was the increasing stress rate of loading. This implies that ASD after fusion may be related to habitual movement before and after fusion. More and faster extension is disadvantageous for the facet joints and should be reduced as much as possible.

Observation of sGAG content of human hip joint cartilage in different old age groups based on EPIC micro-CT.

OBJECTIVES: To observe the age-related changes of sulfated glycosaminoglycan (sGAG) content of hip joint cartilage of elderly people based on Equilibrium Partitioning of an Ionic Contrast Agent (EPIC) micro-CT. METHODS: Seventy human hip cartilage-bone samples were collected from hip-fracture patients (ages 51-96) and divided into five groups (10 years in an age group). They were first immersed in 20% concentration of the contrast agent Meglumine Diatrizoate (MD) for 6 h at 37 °C, and then scanned by micro-CT. Following scanning, samples were stained for sGAG with toluidine blue. The X-ray attenuation and sGAG optical density were calculated by image processing. The correlation between X-ray attenuation and sGAG optical density was then analyzed. RESULTS: The X-ray mean attenuation of the cartilage increased by 18.81% from the 50-80 age groups (p < 0.01), but decreased by 7.15% in the 90 age group compared to the 80 age group. The X-ray mean attenuation of the superficial layer and middle layer increased by 31.60 % and 44.68% from the 50-80 age groups, respectively (p < 0.01), but reduced by 4.67% and 6.05% separately in the 90 age group. However, the deep layer showed no significant change with aging. The sGAG optical density showed a linear correlation (r = -0.91, p < 0.01) with the X-ray attenuation. CONCLUSION: The sGAG content of hip joint cartilage varied with aging in elderly people. The changes in superficial layer and middle layer were more evident than deep layer.