Lactate-upregulated NADPH-dependent NOX4 expression via HCAR1/PI3K pathway contributes to ROS-induced osteoarthritis chondrocyte damage.

Increasing evidence shows that metabolic factors are involved in the pathological process of osteoarthritis (OA). Lactate has been shown to contribute to the onset and progression of diseases. While whether lactate is involved in the pathogenesis of OA through impaired chondrocyte function and its mechanism remains unclear. This study confirmed that serum lactate levels were elevated in OA patients compared to healthy controls and were positively correlated with synovial fluid lactate levels, which were also correlated with fasting blood glucose, high-density lipoprotein, triglyceride. Lactate treatment could up-regulate expressions of the lactate receptor hydroxy-carboxylic acid receptor 1 (HCAR1) and lactate transporters in human chondrocytes. We demonstrated the dual role of lactate, which as a metabolite increased NADPH levels by shunting glucose metabolism to the pentose phosphate pathway, and as a signaling molecule up-regulated NADPH oxidase 4 (NOX4) via activating PI3K/Akt signaling pathway through receptor HCAR1. Particularly, lactate could promote reactive oxygen species (ROS) generation and chondrocyte damage, which was attenuated by pre-treatment with the NOX4 inhibitor GLX351322. We also confirmed that lactate could increase expression of catabolic enzymes (MMP-3/13, ADAMTS-4), reduce the synthesis of type II collagen, promote expression of inflammatory cytokines (IL-6, CCL-3/4), and induce cellular hypertrophy and aging in chondrocytes. Subsequently, we showed that chondrocyte damage mediated by lactate could be reversed by pre-treatment with N-Acetyl-l-cysteine (NAC, ROS scavenger). Finally, we further verified in vivo that intra-articular injection of lactate in Sprague Dawley (SD) rat models could damage cartilage and exacerbate the progression of OA models that could be countered by the NOX4 inhibitor GLX351322. Our study highlights the involvement of lactate as a metabolic factor in the OA process, providing a theoretical basis for potential metabolic therapies of OA in the future.

Resistin induces chemokine and matrix metalloproteinase production via CAP1 receptor and activation of p38-MAPK and NF-κB signalling pathways in human chondrocytes.

OBJECTIVES: Adipokine resistin is highly expressed in the serum and synovial uid (SF) of patients with knee osteoarthritis (KOA) but its pathogenic role in KOA remains unclear. We aimed to explore the mechanism of resistin/CAP1 in human KOA chondrocytes. METHODS: We enrolled 103 patients with radiographic KOA and 86 healthy participants as controls. Resistin levels in serum and SF were determined by enzyme-linked immunosorbent assay (ELISA). CAP1 expression was measured in cartilage tissues using immunohistochemistry, quantitative real-time polymerase chain reaction (qRT-PCR), and western blot. Effects of resistin on chondrocytes and CAP1 were evaluated via qRT-PCR and co-immunoprecipitation. The roles of CAP1, p38-MAPK, and NF-κB signalling pathways in KOA development were evaluated using adenovirus-mediated CAP1 short hairpin RNA, qRT-PCR, western blot, and ELISA. RESULTS: Resistin expression in serum and SF was elevated in severe radiographic KOA. CAP1 levels were higher in KOA cartilage and were positively correlated with resistin expression. Resistin promoted CCL3, CCL4, MMP13, and ADAMTS-4 expression through the CAP1 receptor. Resistin also directly bound to CAP1, as confirmed by co-immunoprecipitation. CAP1 knockdown in chondrocytes attenuated resistin-induced expression of CCL3, CCL4, MMP13, and ADAMTS-4 and activated p38-MAPK and NF-κB signalling pathways. CONCLUSIONS: Resistin binds CAP1 and upregulates the expression of proinflammatory cytokines and matrix-degrading enzymes via p38-MAPK and NF-κB signalling in human chondrocytes.

Novel Insight Into Glycosaminoglycan Biosynthesis Based on Gene Expression Profiles.

Glycosaminoglycans (GAGs) including chondroitin sulfate, dermatan sulfate, heparan sulfate, and keratan sulfate, except for hyaluronan that is a free polysaccharide, are covalently attached to core proteins to form proteoglycans. More than 50 gene products are involved in the biosynthesis of GAGs. We recently developed a comprehensive glycosylation mapping tool, GlycoMaple, for visualization and estimation of glycan structures based on gene expression profiles. Using this tool, the expression levels of GAG biosynthetic genes were analyzed in various human tissues as well as tumor tissues. In brain and pancreatic tumors, the pathways for biosynthesis of chondroitin and dermatan sulfate were predicted to be upregulated. In breast cancerous tissues, the pathways for biosynthesis of chondroitin and dermatan sulfate were predicted to be up- and down-regulated, respectively, which are consistent with biochemical findings published in the literature. In addition, the expression levels of the chondroitin sulfate-proteoglycan versican and the dermatan sulfate-proteoglycan decorin were up- and down-regulated, respectively. These findings may provide new insight into GAG profiles in various human diseases including cancerous tumors as well as neurodegenerative disease using GlycoMaple analysis.

Two-Dimensional Bismuthene Showing Radiation-Tolerant Third-Order Optical Nonlinearities.

The ever-increasing space exploration enterprise calls for novel and high-quality radiation-resistant materials, among which nonlinear optical materials and devices are particularly scarce. Two-dimensional (2D) materials have shown promising potential, but the radiation effects on their nonlinear optical properties remain largely elusive. We previously fabricated 2D bismuthene for mode-locking sub-ns laser; herein, their space adaption was evaluated under a simulated space radiation environment. The as-synthesized thin layers of bismuthene exhibited strong third-order nonlinear optical responses extending into the near-infrared region. Remarkably, when exposed to 60Co γ-rays and electron irradiation, the bismuthene showed only slight degradation in saturable absorption behaviors that were critical for mode-locking in space. Ultrafast spectroscopy was applied to address the radiation effects and damage mechanisms that are difficult to understand by routine techniques. This work offers a new bottom-up approach for preparing 2D bismuthene, and the elucidation of its fundamental excited-state dynamics after radiation also provides a guideline to optimize the material for eventual space applications.

Global mapping of glycosylation pathways in human-derived cells.

Glycans are one of the fundamental classes of macromolecules and are involved in a broad range of biological phenomena. A large variety of glycan structures can be synthesized depending on tissue or cell types and environmental changes. Here, we developed a comprehensive glycosylation mapping tool, termed GlycoMaple, to visualize and estimate glycan structures based on gene expression. We informatically selected 950 genes involved in glycosylation and its regulation. Expression profiles of these genes were mapped onto global glycan metabolic pathways to predict glycan structures, which were confirmed using glycomic analyses. Based on the predictions of N-glycan processing, we constructed 40 knockout HEK293 cell lines and analyzed the effects of gene knockout on glycan structures. Finally, the glycan structures of 64 cell lines, 37 tissues, and primary colon tumor tissues were estimated and compared using publicly available databases. Our systematic approach can accelerate glycan analyses and engineering in mammalian cells.

Metagenomics approach to identify lignocellulose-degrading enzymes in the gut microbiota of the Chinese bamboo rat cecum

BACKGROUND: Lignocellulose is considered a renewable organic material, but the industrial production of biofuel from lignocellulose is challenging because of the lack of highly active hydrolytic enzymes. The guts of herbivores contain many symbiotic microorganisms that have evolved to hydrolyze plant lignocellulose. Chinese bamboo rats mainly consume high-fiber foods, indicating that some members of the intestinal tract microbiota digest lignocellulose, providing these rats with the energy required for growth. RESULTS: Here, we used metagenomics to analyze the diversity and functions of the gut microbiota in Chinese bamboo rats. We identified abundant populations of lignocellulose-degrading bacteria, whose main functions involved carbohydrate, amino acid, and nucleic acid metabolism. We also found 587 carbohydrate-active enzyme genes belonging to different families, including 7 carbohydrate esterase families and 21 glycoside hydrolase families. The glycoside hydrolase 3, glycoside hydrolase 1, glycoside hydrolase 43, carbohydrate esterase 4, carbohydrate esterase 1, and carbohydrate esterase 3 families demonstrated outstanding performance. CONCLUSIONS: The microbes and enzymes identified in our study expand the existing arsenal of proficient degraders and enzymes for lignocellulosic biofuel production. This study also describes a powerful approach for targeting gut microbes and enzymes in numerous industries.

Octyl-2-cyanoacrylate tissue adhesive without subcuticular suture for wound closure after total hip arthroplasty: a prospective observational study on thirty-two cases with controls for 3 months follow-up.

BACKGROUND: Whether using tissue adhesive alone after subcutaneous suture can close the skin incision with safety as well as cosmetic appearance after total hip arthroplasty was not clear. METHODS: A prospective study was conducted. The same surgical methods were consistent throughout the entire study. After implanting prosthesis, the joint capsule was reconstructed. Fascial and subcutaneous layer were respectively closed by continuous running barbed suture. Patients were randomized allocated to group A with octyl-2-cyanoacrylate tissue adhesive alone, to group B with tissue adhesive after continuous subcuticular suture, or to group C with skin staples. Time of closure, drainage, pain, wound complications, and cosmesis were compared. All data were analyzed statistically. RESULTS: There was no significant difference in drainage, Visual Analog Scale score or early wound complications between the three groups. However, there was significant difference in time of closure (P = 0.013). In pairwise comparison, time of closure in groups A and B was significantly longer than those in group C (P = 0.001 and P = 0.023, respectively); time of closure in group A was significantly shorter than those in group B (P = 0.003). Patient and Observer Scar Assessment Scale total scores were not significantly different at 6 weeks and 3 months postoperatively (P = 0.078 and P = 0.284, respectively). CONCLUSION: Tissue adhesive without subcuticular suture was similar with a combination of subcuticular suture and tissue adhesive as well skin staples in terms of safety and cosmetic appearance after total hip arthroplasty.

Assessment of pelvic morphology using 3D imaging and analysis in unilateral Crowe-IV developmental dysplasia of the hip.

AIMS: Morphological abnormalities are present in patients with developmental dysplasia of the hip (DDH). We studied and compared the pelvic anatomy and morphology between the affected hemipelvis with the unaffected side in patients with unilateral Crowe type IV DDH using 3D imaging and analysis. METHODS: A total of 20 patients with unilateral Crowe-IV DDH were included in the study. The contralateral side was considered normal in all patients. A coordinate system based on the sacral base (SB) in a reconstructed pelvic model was established. The pelvic orientations (tilt, rotation, and obliquity) of the affected side were assessed by establishing a virtual anterior pelvic plane (APP). The bilateral coordinates of the anterior superior iliac spine (ASIS) and the centres of hip rotation were established, and parameters concerning size and volume were compared for both sides of the pelvis. RESULTS: The ASIS on the dislocated side was located inferiorly and anteriorly compared to the healthy side (coordinates on the y-axis and z-axis; p = 0.001; p = 0.031). The centre of hip rotation on the dislocated side was located inferiorly and medially compared to the healthy side (coordinates on the x-axis and the y-axis; p < 0.001; p = 0.003). The affected hemipelvis tilted anteriorly in the sagittal plane (mean 8.05° (SD 3.57°)), anteriorly rotated in the transverse plane (mean 3.31° (SD 1.41°)), and tilted obliquely and caudally in the coronal plane (mean 2.04° (SD 0.81°)) relative to the healthy hemipelvis. The affected hemipelvis was significantly smaller in the length, width, height, and volume than the healthy counterpart. (p = 0.014; p = 0.009; p = 0.035; p = 0.002). CONCLUSION: Asymmetric abnormalities were identified on the affected hemipelvis in patients with the unilateral Crowe-IV DDH using 3D imaging techniques. Improved understanding of the morphological changes may influence the positioning of the acetabular component at THA. Acetabular component malpositioning errors caused by anterior tilt of the affected hemi pelvis and the abnormal position of the affected side centre of rotation should be considered by orthopaedic surgeons when undertaking THA in patients with Crowe-IV DDH. Cite this article: Bone Joint J 2020;102-B(10):1311-1318.

The protective effort of GPCR kinase 2-interacting protein-1 in neurons via promoting Beclin1-Parkin induced mitophagy at the early stage of spinal cord ischemia-reperfusion injury.

In spinal cord ischemia-reperfusion (I/R) injury, large amounts of reactive oxygen species can cause mitochondrial damage. Therefore, mitophagy acts as the main mechanism for removing damaged mitochondria and protects nerve cells. This study aimed to illustrate the important role of GPCR kinase 2-interacting protein-1 (GIT1) in mitophagy in vivo and in vitro. The level of mitophagy in the neurons of Git1 knockout mice was significantly reduced after ischemia-reperfusion. However, the overexpression of adeno-associated virus with Git1 promoted mitophagy and inhibited the apoptosis of neurons. GIT1 regulated the phosphorylation of Beclin-1 in Thr119, which could promote the translocation of Parkin to the mitochondrial outer membrane. This process was independent of PTEN-induced kinase 1 (PINK1), but it could not rescue the role in the absence of PINK1. Overall, GIT1 enhanced mitophagy and protected neurons against ischemia-reperfusion injury and, hence, might serve as a new research site for the protection of ischemia-reperfusion injury.

Slipped capital femoral epiphysis in an adult with congenital hypopituitarism: A case report.

RATIONALE: Slipped capital femoral epiphysis (SCFE) is a common hip problem in adolescents, usually individuals between 8 and 15 years old. Because of the frequent finding of growth abnormalities in affected children, various endocrine disturbances have been reported as the cause of the disease. However, there are few case reports of older patients in previous literature. To the best of our knowledge, congenital hypopituitarism with normal growth hormone (GH) level has not been reported. PATIENT CONCERNS: We describe a 29-year-old man who had a 3-month history of pain in the left hip with tall stature and unobvious secondary sexual characteristics. Laboratory testing showed low thyroxine, low cortisol, low follicle-stimulating hormone, low luteinizing hormone, low testosterone, but normal GH. DIAGNOSES: Brain magnetic resonance imaging showed pituitary hypoplasia. An anteroposterior pelvis radiograph showed severe varus SCFE in the left hip, it was also confirmed with computed tomography scans. INTERVENTIONS: The patient was treated with levothyroxine, hydrocortisone, and testosterone replacement therapy before surgery. We performed open reduction and anatomical reduction by Dunn's procedure. OUTCOME: We have followed this patient for 6 months, the left hip mobility gradually improved. No slip in the contralateral proximal femoral physis has been observed. LESSONS: When unobvious secondary sexual characteristics and body abnormalities were found in clinical practice, endocrine condition should be evaluated, since the contralateral side may prone to slip due to the lack of endocrine therapy.

Transcriptome analysis revealed pivotal transporters involved in the reduction of cadmium accumulation in pak choi (Brassica chinensis L.) by exogenous hydrogen-rich water.

Hydrogen-rich water (HRW) has been widely used in research on plant resistance to Cd. However, the underlying molecular mechanism of HRW in ameliorating cadmium stress in vegetables is largely unknown. In this study, the RNA-sequencing analyses were used to characterize the role of HRW in the alleviation of Cd toxicity in Chinese cabbage seedlings. Based on the obtained results, two genes encoding metal ionic transporters, BcIRT1 and BcZIP2 were ultimately selected out. Then, a systematic validation of the metal ion transport function of these two ZIP-encoding genes of pak choi were performed via a yeast transformation system. The results showed that BcIRT1 and BcZIP2 increased the sensitivity of different yeast mutant strains to relative metal ionic stresses and facilitated the accumulation of metal ions (Cd2+, Mn2+, Zn2+, and Fe2+) in yeast; thus, it suggests that BcIRT1 and BcZIP2 probably have the ability to transport Cd2+, Mn2+, Zn2+ and Fe2+ in pak choi. The time-course and concentration-dependent expression profiles of BcIRT1 and BcZIP2 showed that as time with HRW increased, the effectiveness of the repression on the expression of BcIRT1 and BcZIP2 increased, and as the seedlings were exposed to increased Cd concentrations, the inhibition of BcIRT1 and BcZIP2 by HRW was also increased. Over all, these findings provide new insights into the genome-wide transcriptome profiles in pak choi and show that HRW reduced Cd uptake probably through inhibiting the expression of transporters related to Cd absorption, BcIRT1 and BcZIP2.

GIT1 contributes to autophagy in osteoclast through disruption of the binding of Beclin1 and Bcl2 under starvation condition.

Approximately 10-15% of all bone fractures do not heal properly, causing patient morbidity and additional medical care expenses. Therefore, better mechanism-based fracture repair approaches are needed. In this study, a reduced number of osteoclasts (OCs) and autophagosomes/autolysosomes in OC can be observed in GPCR kinase 2-interacting protein 1 (GIT1) knockout (KO) mice on days 21 and 28 post-fracture, compared with GIT1 wild-type (GIT1 WT) mice. Furthermore, in vitro experiments revealed that GIT1 contributes to OC autophagy under starvation conditions. Mechanistically, GIT1 interacted with Beclin1 and promoted Beclin1 phosphorylation at Thr119, which induced the disruption of Beclin1 and Bcl2 binding under starvation conditions, thereby, positively regulating autophagy. Taken together, the findings suggest a previously unappreciated role of GIT1 in autophagy of OCs during fracture repair. Targeting GIT1 may be a potential therapeutic approach for bone fractures.

The current status and unmet needs in the management of psoriatic arthritis: Viewpoint from physicians in Taiwan.

BACKGROUND/PURPOSE: To analyze the real-world clinical practice for the treatment of psoriatic arthritis (PsA) and to assess physicians' prescription, difficulties in diagnosis, therapeutic strategy, rationales for biologic therapies and unmet needs in Taiwan. METHODS: We conducted a nationwide cross-sectional observational study by face-to-face in depth interviews with 50 rheumatologists and 30 dermatologists who took care of patients with PsA. RESULTS: The major procedures for recognizing PsA included joint, skin and nail examinations, radiographic imaging, and medical history. More dermatologists established the diagnosis when psoriatic patients with arthritis didn't present with rheumatoid factors (p < 0.05). For milder arthritis, physicians tended to prescribe etanercept in combination with conventional disease-modifying antirheumatic drugs (DMARDs). The efficacy, safety, retention rate, and non-parenteral administration are the major concerns of physicians which are also the primary unmet needs in the current management of PsA. CONCLUSION: This survey showed the status quo in Taiwan of the clinical management for PsA including diagnostic difficulties, therapeutic consideration, rationales for biologic DMARDs selection and unmet needs in treatment. It has indicated that interdisciplinary collaboration may further improve the quality for PsA care. These results may help establish new strategy to develop next generation biologics.

Novel biomolecule lycopene-reduced graphene oxide-silver nanoparticle enhances apoptotic potential of trichostatin A in human ovarian cancer cells (SKOV3).

BACKGROUND: Recently, there has been much interest in the field of nanomedicine to improve prevention, diagnosis, and treatment. Combination therapy seems to be most effective when two different molecules that work by different mechanisms are combined at low dose, thereby decreasing the possibility of drug resistance and occurrence of unbearable side effects. Based on this consideration, the study was designed to investigate the combination effect of reduced graphene oxide-silver nanoparticles (rGO-AgNPs) and trichostatin A (TSA) in human ovarian cancer cells (SKOV3). METHODS: The rGO-AgNPs were synthesized using a biomolecule called lycopene, and the resultant product was characterized by various analytical techniques. The combination effect of rGO-Ag and TSA was investigated in SKOV3 cells using various cellular assays such as cell viability, cytotoxicity, and immunofluorescence analysis. RESULTS: AgNPs were uniformly distributed on the surface of graphene sheet with an average size between 10 and 50 nm. rGO-Ag and TSA were found to inhibit cell viability in a dose-dependent manner. The combination of rGO-Ag and TSA at low concentration showed a significant effect on cell viability, and increased cytotoxicity by increasing the level of malondialdehyde and decreasing the level of glutathione, and also causing mitochondrial dysfunction. Furthermore, the combination of rGO-Ag and TSA had a more pronounced effect on DNA fragmentation and double-strand breaks, and eventually induced apoptosis. CONCLUSION: This study is the first to report that the combination of rGO-Ag and TSA can cause potential cytotoxicity and also induce significantly greater cell death compared to either rGO-Ag alone or TSA alone in SKOV3 cells by various mechanisms including reactive oxygen species generation, mitochondrial dysfunction, and DNA damage. Therefore, this combination chemotherapy could be possibly used in advanced cancers that are not suitable for radiation therapy or surgical treatment and facilitate overcoming tumor resistance and disease progression.

Zinc oxide nanoparticles induce apoptosis and autophagy in human ovarian cancer cells.

BACKGROUND: Zinc oxide nanoparticles (ZnO NPs) are frequently used in industrial products such as paint, surface coating, and cosmetics, and recently, they have been explored in biologic and biomedical applications. Therefore, this study was undertaken to investigate the effect of ZnO NPs on cytotoxicity, apoptosis, and autophagy in human ovarian cancer cells (SKOV3). METHODS: ZnO NPs with a crystalline size of 20 nm were characterized with various analytical techniques, including ultraviolet-visible spectroscopy, X-ray diffraction, transmission electron microscopy, Fourier transform infrared spectroscopy, and atomic force microscopy. The cytotoxicity, apoptosis, and autophagy were examined using a series of cellular assays. RESULTS: Exposure of cells to ZnO NPs resulted in a dose-dependent loss of cell viability, and the characteristic apoptotic features such as rounding and loss of adherence, enhanced reactive oxygen species generation, and loss of mitochondrial membrane potential were observed in the ZnO NP-treated cells. Furthermore, the cells treated with ZnO NPs showed significant double-strand DNA breaks, which are gained evidences from significant number of γ-H2AX and Rad51 expressed cells. ZnO NP-treated cells showed upregulation of p53 and LC3, indicating that ZnO NPs are able to upregulate apoptosis and autophagy. Finally, the Western blot analysis revealed upregulation of Bax, caspase-9, Rad51, γ-H2AX, p53, and LC3 and downregulation of Bcl-2. CONCLUSION: The study findings demonstrated that the ZnO NPs are able to induce significant cytotoxicity, apoptosis, and autophagy in human ovarian cells through reactive oxygen species generation and oxidative stress. Therefore, this study suggests that ZnO NPs are suitable and inherent anticancer agents due to their several favorable characteristic features including favorable band gap, electrostatic charge, surface chemistry, and potentiation of redox cycling cascades.

Electrochemical Stripping of Atomic Oxygen on Single-Crystalline Platinum: Bridging Gas-Phase and Electrochemical Oxidation.

To understand the interaction between Pt and surface oxygenated species in electrocatalysis, this paper correlates the electrochemistry of atomic oxygen on Pt formed in the gas phase with electrochemically generated oxygen species on a variety of single-crystal platinum surfaces. The atomic oxygen adsorbed on single-crystalline Pt electrodes, made by thermal dissociation of molecular oxygen, is used for voltammetry measurements in acidic electrolytes (HClO4 and H2SO4). The essential knowledge of coverage, binding energy, and surface construction of atomic oxygen is correlated with the charge, potential, and shape of voltammograms, respectively. The differences of the voltammograms between the oxide made by thermal dissociation of molecular oxygen and electrochemical oxidation imply that atomic oxygen is not an intermediate of the electrochemical oxidation of Pt(111). The reconstruction of (100) terrace and step and the low-potential stripping of atomic oxygen on (111) step site provide insight into the first stages of degradation of Pt-based electrocatalysts.

Antioxidant activities of polysaccharides obtained from Chlorella pyrenoidosa via different ethanol concentrations.

An ultrasonic-assisted extraction of Chlorella pyrenoidosa polysaccharides (CPP) was carried out using different concentrations of ethanol for precipitation, and named as CPP60, CPP70 and CPP85, respectively. The monosaccharide composition of each polysaccharide (CPP) was determined using gas chromatography (GC) and the antioxidant activity of each was investigated via the reducing power and scavenging activity of hydroxyl radicals, 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals and superoxide anion radicals, respectively. All of the polysaccharides examined possessed antioxidant activity in vitro. CPP70 exhibited stronger scavenging activity against superoxide, DPPH and hydroxyl radicals, when compared with CPP60 and CPP85. This suggests that polysaccharides from C. pyrenoidosa precipitated by a final ethanol concentration of 70%, have the potential to be developed as natural antioxidants for use in food and pharmaceuticals.

Inactivation kinetics of formaldehyde on N-acetyl-ß-D-glucosaminidase from Nile tilapia (Oreochromis niloticus).

Formaldehyde is a widely used sanitizer in aquaculture in China, while the appropriate concentration is not available to be used effectively and without damage to tilapia much less to its reproductive function. N-acetyl-ß-D-glucosaminidase (EC 3.2.1.52, NAGase), hydrolyzing the oligomers of N-acetyl-ß-D-glucosamine into monomer, is proved to be correlated with reproduction of male animals. In this paper, NAGase from spermary of tilapia was chosen as the material to study the effects of formaldehyde on its activity in order to further investigate the effects of formaldehyde use on tilapia reproduction. The results showed the relationship between the residual enzyme activity and the concentration of formaldehyde was concentration dependent, and the IC50 value was estimated to be 3.2 ± 0.1 %. Appropriate concentration of formaldehyde leaded to competitive reversible inhibition on tilapia NAGase. Moreover, formaldehyde could reduce the thermal and pH stability of the enzyme. The inactivation kinetics of formaldehyde on the enzyme was studied using the kinetic method of substrate reaction. The inactivation model was setup, and the rate constants were determined. The results showed that the inactivation of formaldehyde on tilapia NAGase was a slow, reversible reaction with partially residual activity. The results will give some basis to determine the concentration of formaldehyde used in tilapia culture.

The immune factors involved in the pathogenesis, diagnosis, and treatment of Sjogren's syndrome.

Sjogren's syndrome (SS) is a systemic, autoimmune disorder characterized by salivary insufficiency and lymphocytic infiltration of the exocrine glands. Even though the mechanism of its pathology and progression has been researched ever since its discovery, the roles of different parts of immune system remain inconclusive. There is no straightforward and simple theory for the pathogenesis and diagnosis of Sjogren's syndrome because of the multiple kinds and functions of autoantibodies, changing proportion of different T-lymphocyte subsets with the progression of disease, unsuspected abilities of B lymphocytes discovered recently, crosstalk between cytokines connecting the factors mentioned previously, and genetic predisposition that contributes to the initiation of this disease. On the other hand, the number of significant reports and open-label studies of B-cell depletion therapy showing clinical efficacy in sjogren's syndrome has continued to accumulate, which provides a promising future for the patients. In a word, further elucidation of the role of different components of the immune system will open avenues for better diagnosis and treatment of SS, whose current management is still mainly supportive.