Functional Group-driven Competing Mechanism in Electrochemical Reaction and Adsorption/Desorption Processes toward High-capacity Aluminum-Porphyrin Batteries.

Nonaqueous organic aluminum batteries are considered as promising high-safety energy storage devices due to stable ionic liquid electrolytes and Al metals. However, the stability and capacity of organic positive electrodes are limited by their inherent high solubility and low active organic molecules. To address such issues, here porphyrin compounds with rigid molecular structures present stable and reversible capability in electrochemically storing AlCl2+. Comparison between the porphyrin molecules with electron-donating groups (TPP-EDG) and with electron-withdrawing groups (TPP-EWG) suggests that EDG is responsible for increasing both HOMO and LUMO energy levels, resulting in decreased redox potentials. On the other hand, EWG is associated with decreasing both HOMO and LUMO energy levels, leading to promoted redox potentials. EDG and EWG play critical roles in regulating electron density of porphyrin π bond and electrochemical energy storage kinetics behavior. The competitive mechanism between electrochemical redox reaction and de/adsorption processes suggests that TPP-OCH3 delivers the highest specific capacity ~171.8 mAh g-1, approaching a record in the organic Al batteries.

Nickel-Catalyzed Direct Sulfonylation of Styrenes and Unactivated Aliphatic Alkenes with Sulfonyl Chlorides.

A nickel-catalyzed direct sulfonylation of alkenes with sulfonyl chlorides has been developed using 1,10-phenanthroline-5,6-dione as the ligand. Unactivated alkenes and styrenes including 1,1-, 1,2-disubstituted alkenes can be subjected to the protocol, and a wide range of vinyl sulfones was obtained in high to excellent yields with good functional group compatibility. Notably, the process did not allow the desulfonylation of sulfonyl chloride or chlorosulfonylation of alkenes. Radical-trapping experiment supported that a sulfonyl free-radical was likely produced and triggered subsequent transformation in the process.

Theoretical Analysis of Thermophysical Properties of 3D Carbon/Epoxy Braided Composites with Varying Temperature.

A three-dimensional helix geometry unit cell is established to simulate the complex spatial configuration of 3D braided composites. Initially, different types of yarn factors, such as yarn path, cross-sectional shape, properties, and braid direction, are explained. Then, the multiphase finite element method is used to develop a new theoretical calculation procedure based on the unit cell for predicting the impacts of environmental temperature on the thermophysical properties of 3D four-direction carbon/epoxy braided composites. The changing rule and distribution characteristics of the thermophysical properties for 3D four-direction carbon/epoxy braided composites are obtained at temperatures ranging from room temperature to 200 °C. The influences of environmental temperature on the coefficients of thermal expansion (CTE) and the coefficients of thermal conduction (CTC) are evaluated, by which some important conclusions are drawn. A comparison is conducted between theoretical and experimental results, revealing that variations in temperature exert a notable influence on the thermophysical characteristics of 3D four-directional carbon/epoxy braided composites. The theoretical calculation procedure is an effective tool for the mechanical property analysis of composite materials with complex geometries.

Abnormal expression of PRKAG2-AS1 in endothelial cells induced inflammation and apoptosis by reducing PRKAG2 expression.

PRKAG2 is required for the maintenance of cellular energy balance. PRKAG2-AS1, a long non-coding RNA (lncRNA), was found within the promoter region of PRKAG2. Despite the extensive expression of PRKAG2-AS1 in endothelial cells, the precise function and mechanism of this gene in endothelial cells have yet to be elucidated. The localization of PRKAG2-AS1 was predominantly observed in the nucleus, as revealed using nuclear and cytoplasmic fractionation and fluorescence in situ hybridization. The manipulation of PRKAG2-AS1 by knockdown and overexpression within the nucleus significantly altered PRKAG2 expression in a cis-regulatory manner. The expression of PRKAG2-AS1 and its target genes, PRKAG2b and PRKAG2d, was down-regulated in endothelial cells subjected to oxLDL and Hcy-induced injury. This finding suggests that PRKAG2-AS1 may be involved in the mechanism behind endothelial injury. The suppression of PRKAG2-AS1 specifically in the nucleus led to an upregulation of inflammatory molecules such as cytokines, adhesion molecules, and chemokines in endothelial cells. Additionally, this nuclear suppression of PRKAG2-AS1 facilitated the adherence of THP1 cells to endothelial cells. We confirmed the role of nuclear knockdown PRKAG2-AS1 in the induction of apoptosis and inhibition of cell proliferation, migration, and lumen formation through flow cytometry, TUNEL test, CCK8 assay, and cell scratching. Finally, it was determined that PRKAG2-AS1 exerts direct control over the transcription of PRKAG2 by its binding to their promoters. In conclusion, downregulation of PRKAG2-AS1 suppressed the proliferation and migration, promoted inflammation and apoptosis of endothelial cells, and thus contributed to the development of atherosclerosis resulting from endothelial cell injury.

Perioperative care of nipple-areola complex-sparing mastectomy and one-stage breast reconstruction via endoscopic axillary approach for ductal carcinoma in situ: A case report.

RATIONALE: Breast cancer represents a prevalent malignancy that primarily impacts women, with pronounced consequences on their overarching health. The major therapeutic approach, encompassing surgical procedures, can often culminate in mastectomy, potentially inciting psychological turmoil and disorders. PATIENT CONCERNS: A patient was admitted to our facility on May 5, 2023, precipitated by the discovery of bilateral breast masses during a routine physical examination conducted 3 days before admission. DIAGNOSIS: The breasts were symmetric, with the right nipple inverted and a palpable mass in the upper outer quadrant of the right breast, measuring approximately 5 cm × 4 cm. The mass was firm with indistinct borders, relatively regular morphology, poor mobility, and no tenderness. Outpatient color Doppler ultrasound revealed heterogeneous echogenicity in the right breast, classified as Breast Imaging Reporting and Data System (BI-RADS) category 0, along with multiple ductal dilatations. The left breast exhibited a hypoechoic area (BI-RADS 3), indicative of proliferative changes. Radiographic mammography confirmed diffuse changes in the right breast (BI-RADS 0) and proliferative signs in the left breast (BI-RADS 2). Biopsy results reveal significant atypical ductal hyperplasia consistent with intermediate-grade ductal carcinoma in situ. This patient was diagnosed as ductal carcinoma in situ of the right breast (cTisN0M0 and Stage 0), accompanied by a left breast mass. INTERVENTIONS: On May 15, 2023, the patient was readmitted for further surgical intervention. Following relevant auxiliary examinations, the patient underwent nipple-areola complex-sparing radical mastectomy for the right breast, sentinel lymph node biopsy in the right axillary area, prosthesis-based breast reconstruction for the right breast, and microrotatotomy of the left breast mass on the left side on May 17. OUTCOMES: The patient made a successful recovery under scrupulous perioperative supervision and was discharged 7 days post-surgery. LESSONS: The axillary approach for endoscopic mammary gland excision and immediate implant reconstruction permits patients to preserve the esthetics of the female form while undergoing conventional medical treatment. This methodology considerably enhances the psychophysical health of the patients, thereby marking it as an advantageous practice worthy of broad dissemination in the medical community.

Abnormal expression of PRKAG2-AS results in dysfunction of cardiomyocytes through regulating PRKAG2 transcription by interacting with PPARG.

The role of PRKAG2 in the maintenance of heart function is well established, but little is known about how PRKAG2 is regulated in cardiomyocytes. In this study, we investigated the role of the lncRNA PRKAG2-AS, which is present at the PRKAG2 promoter, in the regulation of PRKAG2 expression. PRKAG2-AS expression was predominantly nuclear, as determined by RNA nucleoplasmic separation and fluorescence in situ hybridization. Knockdown of PRKAG2-AS in the nucleus, but not the cytoplasm, significantly decreased the expression of PRKAG2b and PRKAG2d. Interestingly, we found that PRKAG2-AS and its target genes, PRKAG2b and PRKAG2d, were reduced in the hearts of patients with ischemic cardiomyopathy, suggesting a potential role for PRKAG2-AS in myocardial ischemia. Indeed, knockdown of PRKAG2-AS in the nucleus resulted in apoptosis of cardiomyocytes. We further elucidated the mechanism by which PRKAG2-AS regulates PRKAG2 transcription by identifying 58 PRKAG2-AS interacting proteins. Among them, PPARG was selected for further investigation based on its correlation and potential interaction with PRKAG2-AS in regulating transcription. Overexpression of PPARG, or its activation with rosiglitazone, led to a significant increase in the expression of PRKAG2b and PRKAG2d in cardiomyocytes, which could be attenuated by PRKAG2-AS knockdown. This finding suggests that PRKAG2-AS mediates, at least partially, the protective effects of rosiglitazone on hypoxia-induced apoptosis. However, given the risk of rosiglitazone in heart failure, we also examined the involvement of PRKAG2-AS in this condition and found that PRKAG2-AS, as well as PRKAG2b and PRKAG2d, was elevated in hearts with dilated cardiomyopathy (DCM) and that overexpression of PRKAG2-AS led to a significant increase in PRKAG2b and PRKAG2d expression, indicating that up-regulation of PRKAG2-AS may contribute to the mechanism of heart failure by promoting transcription of PRKAG2. Consequently, proper expression of PRKAG2-AS is essential for maintaining cardiomyocyte function, and aberrant PRKAG2-AS expression induced by hypoxia or other stimuli may cause cardiac dysfunction.

Intracranial infection and sepsis in infants caused by Salmonella derby: A case report.

BACKGROUND: Salmonella derby (S. derby) is a Gram-negative diplococcus that is common in the digestive tract. Infected patients generally experience symptoms such as fever and diarrhea. Mild cases are mostly self-healing gastroenteritis, and severe cases can cause fatal typhoid fever. Clinical cases are more common in children. The most common form of S. derby infection is self-healing gastroenteritis, in which, fever lasts for about 2 d and diarrhea for < 7 d. S. derby can often cause bacterial conjunctivitis, pneumonia, endocarditis, peritonitis and urethritis. However, intracranial infections in infants caused by S. derby are rare in clinical practice and have not been reported before in China. CASE SUMMARY: A 4-mo-old female infant had recurrent fever for 2 wk, with a maximum body temperature of around 39.4°C. Treatment for infectious fever in a local hospital was ineffective, and she was admitted to our hospital. Before admission, there was one sudden convulsion, characterized by unclear consciousness, limb twitching, gaze in both eyes, and slight cyanosis on the face. Cerebrospinal fluid (CSF) culture was positive for Gram-negative bacilli, which conformed to S. derby. After treatment with meropenem and ceftriaxone antibiotics, the patient was discharged home in a clinically stable state after 4 wk of treatment. CONCLUSION: We reported a rare case of S. derby cultured in CSF. S. derby enters the CSF through the blood-brain barrier, causing purulent meningitis. If not treated timeously, it can lead to serious, life-threatening infection.

Metal-Free Selective Ortho-C-H Amidation of Hypervalent(III) Iodobezenes with N-Methoxy Amides under Mild Conditions.

A metal-free selective ortho-C-H amidation of aryl iodines(III) with the use of N-methoxy amides as aminating reagents under mild conditions is described here. In the protocol, excellent chemoselectivity and high regioselectivity were obtained. Notably, the iodine substituent rendered the amidation product suitable to be used for further elaboration.

Effects of dietary oat supplementation on carcass traits, muscle metabolites, amino acid profiles, and its association with meat quality of Small-tail Han sheep.

Oat supplementation of the ruminant diet can improve growth performance and meat quality traits, but the role of muscle metabolites has not been evaluated. This study aimed to establish whether oat grass supplementation (OS) of Small-tail Han sheep improved growth performance and muscle tissue metabolites that are associated with better meat quality and flavor. After 90-day, OS fed sheep had higher live-weight and carcass-weight, and lower carcass fat. Muscle metabolomics analysis showed that OS fed sheep had higher levels of taurine, l-carnitine, inosine-5'-monophospgate, cholic acid, and taurocholic acid, which are primarily involved in taurine and hypotaurine metabolism, purine metabolism, and bile acid biosynthesis and secretion, decreased fat accumulation and they promote functional or flavor metabolites. OS also increased muscle levels of amino acids that are attributed to better quality and flavorsome mutton. These findings provided further evidence for supplementing sheep with oat grass to improve growth performance and meat quality.

Epigenetics comprehensive experimental course based on the integration of science and education to cultivate students' ability of cutting-edge innovation.

The integration of science and education is an effective way for universities to cultivate students in cutting-edge innovative interests. Epigenetics is the expansion of classical genetics, the corresponding experimental courses of which have not been integrated into the current teaching system. In this paper, by taking advantage of our laboratory's research on the DNA methylation maintenance gene, OsMET1-2 in rice, we have integrated our innovative findings in the education curriculum, and built a comprehensive teaching system on experimentation research, which greatly stimulates the curiosity of the students. Taking the OsMET1-2 mutants and its isogenic wild-type rice plants as experimental materials, this course has successfully demonstrated a causal link between genetic mutation and epigenetic variation, a topic widely interested by the students in learning genetics and epigenetics. Through the practice of this course, students have a deeper understanding of the important role of epigenetic modifications, their scientific research capabilities have been greatly improved, thereby strongly supporting the cultivation of top innovative talents among the students.

Inhibition of UGT1A1*1 and UGT1A1*6 catalyzed glucuronidation of SN-38 by silybins.

UGT1A1 is the main enzyme that catalyzes the metabolic elimination and detoxification of SN-38, the active form of the drug irinotecan. Milk thistle products have been used widely to protect the liver from injury associated with the use of chemotherapeutic agents. To evaluate whether SN-38 metabolism can be affected by milk thistle products, the inhibitory effects of silybins on UGT1A1*1 and UGT1A1*6 were evaluated in the present investigation. Both silybin A and silybin B potently inhibited SN-38 glucuronidation catalyzed by UGT1A1*1 or UGT1A1*6. It was noteworthy that silybin A and silybin B showed synergistic effect in UGT1A1*1 microsomes at concentration around IC50, while additive effect in UGT1A1*6. According to the predicted AUCi/AUC ratios (the ratio of the area under the plasma concentration-time curve of SN-38 in the presence and absence of silybins), the coadministration of irinotecan and several milk thistle products, including silybin-phosphatidylcholine complex, two Legalon capsules, four Silymarin tablets or four Liverman capsules, may lead to clinically significant herb-drug interactions (HDI) via UGT1A1 inhibition. Meanwhile, Rgut values were much higher than 11 in all the groups, indicating potential HDI due to intestinal UGT1A1 inhibition.

Photoredox-Catalyzed Acyl Lactonization of Alkenes with Aldehydes: Synthesis of Acyl Lactones.

An acyl lactonization of alkenes with aldehydes under visible-light photoredox catalysis is described. With the protocol, a broad scope of alkenoic acids and aldehydes could be compatible and good functional group tolerance is obtained. A series of acyl lactones are obtained with isolated yields ranging from 50-95%. Mechanistic studies revealed that the transformation should proceed via a radical chain process.

Long Noncoding RNA BCYRN1 Recruits BATF to Promote TM4SF1 Upregulation and Enhance HCC Cell Proliferation and Invasion.

Hepatocellular carcinoma (HCC) is a common form of cancer for which a subset of reliable clinical biomarkers has been defined. However, other factors including long noncoding RNAs (lncRNAs) can also regulate HCC development. This study was thus designed to understand how the lncRNA Brain cytoplasmic RNA 1 (BCYRN1) modulates HCC progression. Bioinformatics approaches were used to identify genes, lncRNAs, and transcription factors that were differentially expressed in the context of HCC, after which the relative expression of BCYRN1 in HCC and control tissues was assessed via qPCR. The ability of BCYRN1 to bind the transcription factor BATF was further evaluated in an RNA immunoprecipitation (RIP) assay, while chromatin immunoprecipitation (ChIP) was used to gauge the binding of the TM4SF1 promoter by BATF. Luciferase reporter assays were also used to assess the association between BCYRN1 and the TM4SF1 promoter. Subsequent loss- and gain-of-function assays were then conducted to explore the effects of altering BCYRN1 expression levels on the proliferative, invasive, and migratory activity of HCC cells. BCYRN1 upregulation was associated with poorer clinical outcomes in HCC patients, and knocking down this lncRNA impaired HCC cell migration and invasion. From a mechanistic perspective, BATF was recruited to the TM4SF1 promoter by BCYRN1, and reducing the expression of this lncRNA was sufficient to constrain xenograft tumor growth in mice. These results highlight BCYRN1 as a putative therapeutic target in HCC tumors.

Effects of low molecular weight heparin combined with hyperbaric oxygen on neurologic function and coagulation factors in patients with intracranial venous thrombosis.

OBJECTIVE: To investigate the effects of low molecular weight heparin (LMWH) combined with hyperbaric oxygen (HBO) on the neurologic function and coagulation factors of patients with intracranial venous thrombosis (ICVT). METHODS: The clinical data of 80 patients with ICVT admitted to the No. 2 Hospital of Baoding from February 2020 to January 2021 were retrospectively analyzed. Patients were assigned to a control group (n=32) and a research group (n=48) according to different treatment methods. The neurological function score, and the levels of D-dimer (D-D), fibrinogen (FIB), tumor necrosis factor-α (TNF-α), and C-reactive protein (CRP) were compared between the two groups. The two groups were also compared regarding the curative effect, toxic and side effects, as well as quality of life (QoL). RESULTS: After treatment, the National Institutes of Health Stroke Scale (NIHSS) score was significantly lower in the research group compared to the control group. At 1, 2 and 3 weeks after treatment, the levels of D-D and FIB, as well as inflammatory factors TNF-α and CRP were lower in the research group compared to the control group. The overall response rate was significantly higher in the research group compared to the control group, while there was no significant difference in the total incidence of toxic and adverse effects between the two groups. After treatment, the QoL of patients assessed by the Generic Quality of Life Inventory-74 (GQOLI-74) from the domains of physical, social, and psychological function as well as material life status was significantly better in the research group. CONCLUSIONS: LMWH combined with HBO can effectively improve the clinical efficacy and neurologic function of patients with ICVT and reduce the levels of coagulation factors and inflammatory factors.

Increased MCL-1 synthesis promotes irradiation-induced nasopharyngeal carcinoma radioresistance via regulation of the ROS/AKT loop.

Worldwide, nasopharyngeal carcinoma (NPC) is a rare head and neck cancer; however, it is a common malignancy in southern China. Radiotherapy is the most important treatment strategy for NPC. However, although radiotherapy is a strong tool to kill cancer cells, paradoxically it also promotes aggressive phenotypes. Therefore, we mimicked the treatment process in NPC cells in vitro. Upon exposure to radiation, a subpopulation of NPC cells gradually developed resistance to radiation and displayed cancer stem-cell characteristics. Radiation-induced stemness largely depends on the accumulation of the antiapoptotic myeloid cell leukemia 1 (MCL-1) protein. Upregulated MCL-1 levels were caused by increased stability and more importantly, enhanced protein synthesis. We showed that repeated ionizing radiation resulted in persistently enhanced reactive oxygen species (ROS) production at a higher basal level, further promoting protein kinase B (AKT) signaling activation. Intracellular ROS and AKT activation form a positive feedback loop in the process of MCL-1 protein synthesis, which in turn induces stemness and radioresistance. AKT/MCL-1 axis inhibition attenuated radiation-induced resistance, providing a potential target to reverse radiation therapy-induced radioresistance.

Visible-Light Photoredox-Catalyzed Sulfonyl Lactonization of Alkenoic Acids with Sulfonyl Chlorides for Sulfonyl Lactone Synthesis.

A visible-light photoredox-catalyzed sulfonyl lactonization of unsaturated carboxylic acids with sulfonyl chlorides is described. This reaction features good functional group tolerance and a broad substrate scope, providing a simple and efficient protocol to access a wide range of sulfonyl lactones in high to excellent yields. Preliminary mechanistic investigations suggested that a free-radical pathway should be involved in the process.

Immune Cell Infiltration as Signatures for the Diagnosis and Prognosis of Malignant Gynecological Tumors.

Background Malignant gynecological tumors are the main cause of cancer-related deaths in women worldwide and include uterine carcinosarcomas, endometrial cancer, cervical cancer, ovarian cancer, and breast cancer. This study aims to determine the association between immune cell infiltration and malignant gynecological tumors and construct signatures for diagnosis and prognosis. Methods We acquired malignant gynecological tumor RNA-seq transcriptome data from the TCGA database. Next, the "CIBERSORT" algorithm calculated the infiltration of 22 immune cells in malignant gynecological tumors. To construct diagnosis and prognosis signatures, step-wise regression and LASSO analyses were applied, and nomogram and immune subtypes were further identified. Results Notably, Immune cell infiltration plays a significant role in tumorigenesis and development. There are obvious differences in the distribution of immune cells in normal, and tumor tissues. Resting NK cells, M0 Macrophages, and M1 Macrophages participated in the construction of the diagnostic model, with an AUC value of 0.898. LASSO analyses identified a risk signature including T cells CD8, activated NK cells, Monocytes, M2 Macrophages, resting Mast cells, and Neutrophils, proving the prognostic value for the risk signature. We identified two subtypes according to consensus clustering, where immune subtype 3 presented the highest risk. Conclusion We identified diagnostic and prognostic signatures based on immune cell infiltration. Thus, this study provided a strong basis for the early diagnosis and effective treatment of malignant gynecological tumors.

Copper-Catalyzed Intermolecular C(sp2)-H Amination with Electrophilic O-Benzoyl Hydroxylamines.

A copper-catalyzed intermolecular electrophilic amination of benzamides with O-benzoyl hydroxylamines was achieved with the assistance of an 8-aminoquinolyl group. With this protocol, good compatibility was observed for a variety of aryl amides and heteroaryl amides, and excellent tolerance with various functional groups was achieved. Significantly, the monoaminated product was overwhelmingly delivered under the simple reaction conditions. Preliminary mechanistic investigations suggested that a radical pathway should be excluded and C-H activation be potentially the rate-determining step.

Elevated RBP-Jκ and CXCL11 Expression in Colon Cancer is Associated with an Unfavorable Clinical Outcome.

INTRODUCTION: This study aims at exploring the expression and significance of recombination signal-binding protein for immunoglobulin kappa J region (RBP-Jκ) and C-X-C motif chemokine 11 (CXCL11) in human colon cancer tissues. METHODS: The RBP-Jκ and CXCL11 expression levels were assessed by immunohistochemistry and quantitative real-time polymerase chain reaction (qRT-PCR) in patients with colon cancer, and their prognostic significance was evaluated. RESULTS: Through analyzing 342 samples of colon cancer patients treated at our institution, increased expression of RBP-Jκ and CXCL11 was found in human colon cancer specimens compared with matched paratumorous normal specimens (P<0.001). A positive correlation was found between RBP-Jκ expression and CXCL11 expression (P<0.001). High RBP-Jκ expression was significantly associated with poorly differentiated tumors (P=0.005), invasion beyond propria muscularis (P=0.025), lymph node metastases (P=0.005), distant metastasis (P<0.001), advanced tumor-node-metastasis (TNM) stage (P=0.004), and a shorter overall survival (P<0.001). An increase in CXCL11 protein expression was associated with poorly differentiated tumors (P=0.015), invasion beyond propria muscularis (P=0.029), lymph node metastases (P=0.031), distant metastasis (P=0.045), advanced TNM stage (P=0.026), and a shorter overall survival of patients (P<0.001). In multivariate Cox regression analysis, RBP-Jκ protein expression (P=0.036), CXCL11 protein expression (P=0.001), differentiation (P<0.001), depth of invasion (P=0.009), distant metastasis (P<0.001), and TNM stage (P<0.001) were independent prognostic indicators of colon cancer. CONCLUSION: High expression of RBP-Jκ is closely associated with high CXCL11 expression, which represents a risk factor for the poor overall survival of colon cancer patients.

Expression and role of specificity protein 1 and collagen I in recurrent pterygial tissues.

AIM: To investigate the expression profiles of the transcription factor specificity protein 1 (Sp1) and collagen I in recurrent pterygial tissues. What is more, to compare the changes of Sp1 and collagen I among primary pterygial tissue, recurrent pterygial tissue and conjunctival tissue. METHODS: In the prospective study, we collected the pterygial tissues of 40 patients who underwent resection of primary pterygial tissue and recurrent pterygial tissue, and the conjunctival tissues of 10 patients with enucleation due to trauma. The relative expression levels of Sp1 and collagen I were analyzed by reverse transcription quantitative-polymerase chain reaction and Western blot. Paired t-test was performed to compare the Sp1 and collagen I of recurrent pterygial tissues, as well as the primary pterygial tissues and conjunctival tissues. In further, Pearson's hypothesis testing of correlation coefficients was used to compare the correlations of Sp1 and Collagen I. RESULTS: The content of Sp1 and collagen I mRNA and protein was significantly greater in recurrent pterygial tissue than that was in primary and conjunctival tissue (P<0.05). There was a positive correlation between the mRNA and protein levels of Sp1 and collagen I in recurrent pterygial tissues (protein: r=0.913, P<0.05; mRNA: r=0.945, P<0.05). CONCLUSION: Sp1 and collagen I are expressed in normal conjunctival, primary, and recurrent pterygial tissues, but expression is significantly greater in the latter. Sp1 and collagen I may be involved in the regulation of the development of recurrent pterygium.