Structure and function of the pyridoxal 5'-phosphate-dependent (PLP) threonine deaminase IlvA1 from Pseudomonas aeruginosa PAO1.

IlvA1, a pyridoxal phosphate-dependent (PLP) enzyme, catalyzes the deamination of l-threonine and l-serine to yield 2-ketobutyric acid or pyruvate. To gain insights into the function of IlvA1, we determined its crystal structure from Pseudomonas aeruginosa to 2.3 Å. Density for a 2-ketobutyric acid product was identified in the active site and a putative allosteric site. Activity and substrate binding assays confirmed that IlvA1 utilizes l-threonine, l-serine, and L-allo-threonine as substrates. The enzymatic activity is regulated by the end products l-isoleucine and l-valine. Additionally, the efficiency of d-cycloserine and l-cycloserine inhibitors on IlvA1 enzymatic activity was examined. Notably, site-directed mutagenesis confirmed the active site residues and revealed that Gln165 enhances the enzyme activity, emphasizing its role in substrate access. This work provides crucial insights into the structure and mechanism of IlvA1 and serves as a starting point for further functional and mechanistic studies of the threonine deaminase in P. aeruginosa.

Deep-learning based flat-fielding quantitative phase contrast microscopy.

Quantitative phase contrast microscopy (QPCM) can realize high-quality imaging of sub-organelles inside live cells without fluorescence labeling, yet it requires at least three phase-shifted intensity images. Herein, we combine a novel convolutional neural network with QPCM to quantitatively obtain the phase distribution of a sample by only using two phase-shifted intensity images. Furthermore, we upgraded the QPCM setup by using a phase-type spatial light modulator (SLM) to record two phase-shifted intensity images in one shot, allowing for real-time quantitative phase imaging of moving samples or dynamic processes. The proposed technique was demonstrated by imaging the fine structures and fast dynamic behaviors of sub-organelles inside live COS7 cells and 3T3 cells, including mitochondria and lipid droplets, with a lateral spatial resolution of 245 nm and an imaging speed of 250 frames per second (FPS). We imagine that the proposed technique can provide an effective way for the high spatiotemporal resolution, high contrast, and label-free dynamic imaging of living cells.

NFIC mediates m6A mRNA methylation to orchestrate transcriptional and post-transcriptional regulation to represses malignant phenotype of non-small cell lung cancer cells.

BACKGROUND: Multiple genetic and epigenetic regulatory mechanisms are crucial in the development and tumorigenesis process. Transcriptional regulation often involves intricate relationships and networks with post-transcriptional regulatory molecules, impacting the spatial and temporal expression of genes. However, the synergistic relationship between transcription factors and N6-methyladenosine (m6A) modification in regulating gene expression, as well as their influence on the mechanisms underlying the occurrence and progression of non-small cell lung cancer (NSCLC), requires further investigation. The present study aimed to investigate the synergistic relationship between transcription factors and m6A modification on NSCLC. METHODS: The transcription factor NFIC and its potential genes was screened by analyzing publicly available datasets (ATAC-seq, DNase-seq, and RNA-seq). The association of NFIC and its potential target genes were validated through ChIP-qPCR and dual-luciferase reporter assays. Additionally, the roles of NFIC and its potential genes in NSCLC were detected in vitro and in vivo through silencing and overexpression assays. RESULTS: Based on multi-omics data, the transcription factor NFIC was identified as a potential tumor suppressor of NSCLC. NFIC was significantly downregulated in both NSCLC tissues and cells, and when NFIC was overexpressed, the malignant phenotype and total m6A content of NSCLC cells was suppressed, while the PI3K/AKT pathway was inactivated. Additionally, we discovered that NFIC inhibits the expression of METTL3 by directly binding to its promoter region, and METTL3 regulates the expression of KAT2A, a histone acetyltransferase, by methylating the m6A site in the 3'UTR of KAT2A mRNA in NSCLC cells. Intriguingly, NFIC was also found to negatively regulate the expression of KAT2A by directly binding to its promoter region. CONCLUSIONS: Our findings demonstrated that NFIC suppresses the malignant phenotype of NSCLC cells by regulating gene expression at both the transcriptional and post-transcriptional levels. A deeper comprehension of the genetic and epigenetic regulatory mechanisms in tumorigenesis would be beneficial for the development of personalized treatment strategies.

Establishment of low-cost production platforms of polyhydroxyalkanoate bioplastics from Halomonas cupida J9.

Microbial production of polyhydroxyalkanoate (PHA) is greatly restricted by high production cost arising from high-temperature sterilization and expensive carbon sources. In this study, a low-cost PHA production platform was established from Halomonas cupida J9. First, a marker-less genome-editing system was developed in H. cupida J9. Subsequently, H. cupida J9 was engineered to efficiently utilize xylose for PHA biosynthesis by introducing a new xylose metabolism module and blocking xylonate production. The engineered strain J9UΔxylD-P8xylA has the highest PHA yield (2.81 g/L) obtained by Halomonas with xylose as the sole carbon source so far. This is the first report on the production of short- and medium-chain-length (SCL-co-MCL) PHA from xylose by Halomonas. Interestingly, J9UΔxylD-P8xylA was capable of efficiently utilizing glucose and xylose as co-carbon sources for PHA production. Furthermore, fed-batch fermentation of J9UΔxylD-P8xylA coupled to a glucose/xylose co-feeding strategy reached up to 12.57 g/L PHA in a 5-L bioreactor under open and unsterile condition. Utilization of corn straw hydrolysate as the carbon source by J9UΔxylD-P8xylA reached 7.0 g/L cell dry weight (CDW) and 2.45 g/L PHA in an open fermentation. In summary, unsterile production in combination with inexpensive feedstock highlights the potential of the engineered strain for the low-cost production of PHA from lignocellulose-rich agriculture waste.

Effect of acupuncture on regulating IL-17, TNF-ɑ and AQPs in Sjögren's syndrome.

AIM: The aim of the study was to observe the effect of acupuncture on regulating interleukin (IL)-17, tumor necrosis factor (TNF)-ɑ, and aquaporins (AQPs) in Sjögren's syndrome (SS) on patients and on non-obese diabetic (NOD) models. METHODS: Levels of anti-AQP 1, 5, 8, and 9 antibodies, IL-17, and TNF-ɑ in the serum of SS patients were compared prior and following 20 acupuncture treatment visits during 8 weeks. While in murine model, five groups were divided to receive interventions for 4 weeks, including control, model, acupuncture, isoflurane, and hydroxychloroquine. The submaxillofacial gland index, histology, immunohistochemistry of AQP1, 5, salivary flow, together with IL-17, and TNF-ɑ expression in peripheral blood were compared among the groups. RESULTS: Acupuncture reduced IL-17, TNF-ɑ, and immunoglobin A levels, and numeric analog scale of dryness in 14 patients with SS (p < 0.05). The salivary flow was increased, and the water intake decreased in NOD mice receiving acupuncture treatments. IL-17 and TNF-ɑ levels in peripheral serum were down-regulated (p < 0.05) and AQP1, 5 expression in the submandibular glands up-regulated in mice. CONCLUSION: The effect on relieving xerostomia with acupuncture may be achieved by up-regulating the expression of AQP1. AQP5, down-regulating levels of IL-17 and TNF-ɑ, and a decrease in inflammation of glands.

Small Molecule SHP2 Inhibitor LXQ-217 Affects Lung Cancer Cell Proliferation in Vitro and in Vivo.

BACKGROUND: SHP2 is highly expressed in a variety of cancer and has emerged as a potential target for cancer therapeutic agents. The identification of uncharged pTyr mimics is an important direction for the development of SHP2 orthosteric inhibitors. METHODS: Surface plasmon resonance analysis and cellular thermal shift assay were employed to verify the direct binding of LXQ-217 to SHP2. The inhibitory effect of LXQ-217 was characterized by linear Weaver-Burke enzyme kinetic analysis and BIOVIA Discovery Studio. The inhibition of tumor cell proliferation by LXQ-217 was characterized by cell viability assay, colony formation assays and hoechst 33258 staining. The inhibition of lung cancer proliferation in vivo was studied in nude mice after oral administration of LXQ-217. RESULTS: An electroneutral bromophenol derivative, LXQ-217, was identified as a competitive SHP2 inhibitor. LXQ-217 induced apoptosis and inhibited growth of human pulmonary epithelial cells by affecting the RAS-ERK and PI3 K-AKT signaling pathways. Long-term oral administration of LXQ-217 significantly inhibited the proliferation ability of lung cancer cells in nude mice. Moreover, mice administered LXQ-217 orally at high doses exhibited no mortality or significant changes in vital signs. CONCLUSIONS: Our findings on the uncharged orthosteric inhibitor provide a foundation for further development of a safe and effective anti-lung cancer drug.

New targets of TetR-type regulator SLCG_2919 for controlling lincomycin biosynthesis in Streptomyces lincolnensis.

The transcription factor (TF)-mediated regulatory network controlling lincomycin production in Streptomyces lincolnensis is yet to be fully elucidated despite several types of associated TFs having been reported. SLCG_2919, a tetracycline repressor (TetR)-type regulator, was the first TF to be characterized outside the lincomycin biosynthetic cluster to directly suppress the lincomycin biosynthesis in S. lincolnensis. In this study, improved genomic systematic evolution of ligands by exponential enrichment (gSELEX), an in vitro technique, was adopted to capture additional SLCG_2919-targeted sequences harboring the promoter regions of SLCG_6675, SLCG_4123-4124, SLCG_6579, and SLCG_0139-0140. The four DNA fragments were confirmed by electrophoretic mobility shift assays (EMSAs). Reverse-transcription quantitative polymerase chain reaction (RT-qPCR) showed that the corresponding target genes SLCG_6675 (anthranilate synthase), SLCG_0139 (LysR family transcriptional regulator), SLCG_0140 (beta-lactamase), SLCG_6579 (cytochrome P450), SLCG_4123 (bifunctional DNA primase/polymerase), and SLCG_4124 (magnesium or magnesium-dependent protein phosphatase) in ΔSLCGL_2919 were differentially increased by 3.3-, 4.2-, 3.2-, 2.5-, 4.6-, and 2.2-fold relative to those in the parental strain S. lincolnensis LCGL. Furthermore, the individual inactivation of these target genes in LCGL reduced the lincomycin yield to varying degrees. This investigation expands on the known DNA targets of SLCG_2919 to control lincomycin production and lays the foundation for improving industrial lincomycin yields via genetic engineering of this regulatory network.

Structural analysis of the ferric-binding protein KfuA from Klebsiella pneumoniae.

Iron acquisition is an essential process of cell physiology for biological systems. In Klebsiella pneumoniae, the siderophore and ferric-acquisition ABC (ATP-Binding-Cassette) transporter KfuABC is utilized for iron uptake. Initial recognition of the various ferric sources in periplasm and transportation across the cytoplasmic membrane is performed by the substrate-binding protein (SBP) KfuA. Here we report the 2.0 Å resolution crystal structure of KfuA from K. pneumoniae, which crystallizes in the space group P1211 with a single monomer in the asymmetric unit. A bound metal ion reveals the residues required for binding ferric ions. Binding analysis shows that ferric iron and the iron-mimicking gallium bind with high affinity to KfuA. Growth curves show that gallium inhibits growth of K. pneumoniae whereas ferric iron enhances it. This work suggests a mechanism whereby gallium effectively competes with ferric iron, disrupting iron-dependent biological functions via binding to KfuA and leading to heightened antimicrobial efficacy. Significantly, humans lack equivalent ABC transporters like SBP KfuA, underscoring the potential of KfuA as an attractive target for therapeutic intervention.

Structural analysis of molybdate binding protein ModA from Klebsiella pneumoniae.

Klebsiella pneumoniae, a facultative anaerobe, relies on acquiring molybdenum to sustain growth in anaerobic conditions, a crucial factor for the pathogen to establish infections within host environments. Molybdenum plays a critical role in pathogenesis as it forms an essential component of cofactors for molybdoenzymes. K. pneumoniae utilizes the ABC (ATP-Binding-Cassette) transporter encoded by the modABC operon for uptake of the group VI elements molybdenum and tungsten. In this study, we determined the X-ray crystal structures of both the molybdenum-free and molybdenum-bound substrate-binding protein (SBP) ModA from Klebsiella pneumoniae to 2.00 Å and 1.77 Å resolution respectively. ModA crystallizes in the space group P222 with a single monomer in one asymmetric unit. The purified protein remained soluble and specifically bound molybdate and tungstate with Kd values of 6.3 nM and 5.2 nM, respectively. Tungstate competes with molybdate by binding to ModA, resulting in enhanced antimicrobial activity. These data provide a starting point for structural and functional analyses of molybdate transport in K. pneumoniae.

Genome-wide association study identifies GhSAL1 affects cold tolerance at the seedling emergence stage in upland cotton (Gossypium hirsutum L.).

KEY MESSAGE: Genomic analysis of upland cotton revealed that cold tolerance was associated with ecological distribution. GhSAL1 on chromosome D09 negatively regulated cold tolerance of upland cotton. Cotton can undergo low-temperature stress at the seedling emergence stage, which adversely affects growth and yield; however, the regulatory mechanism underlying cold tolerance remains nebulous. Here, we analyze the phenotypic and physiological parameters in 200 accessions from 5 ecological distributions under constant chilling (CC) and diurnal variation of chilling (DVC) stresses at the seedling emergence stage. All accessions were clustered into four groups, of which Group IV, with most germplasms from the northwest inland region (NIR), had better phenotypes than Groups I-III under the two kinds of chilling stresses. A total of 575 significantly associated single-nucleotide polymorphism (SNP) were identified, and 35 stable genetic quantitative trait loci (QTL) were obtained, of which 5 were associated with traits under CC and DVC stress, respectively, while the remaining 25 were co-associated. The accumulation of dry weight (DW) of seedling was associated with the flavonoid biosynthesis process regulated by Gh_A10G0500. The emergence rate (ER), DW, and total length of seedling (TL) under CC stress were associated with the SNPs variation of Gh_D09G0189 (GhSAL1). GhSAL1HapB was the elite haplotype, which increased ER, DW, and TL by 19.04%, 11.26%, and 7.69%, respectively, compared with that of GhSAL1HapA. The results of virus-induced gene silencing (VIGS) experiment and determination of metabolic substrate content preliminarily illustrated that GhSAL1 negatively regulated cotton cold tolerance through IP3-Ca2+ signaling pathway. The elite haplotypes and candidate genes identified in this study could be used to improve cold tolerance at the seedling emergence stage in future upland cotton breeding.

Epilepsy as the symptom of a spinocerebellar ataxia 13 in a patient presenting with a mutation in the KCNC3 gene.

BACKGROUND: The spinocerebellar ataxias (SCAs) refer to a diverse group of neurodegenerative illnesses that vary clinically and genetically. One of the rare subtypes within this group is SCA13, caused by mutations in the KCNC3 gene. Currently, the prevalence of SCA13 remains uncertain, with only a couple of cases being documented in the Chinese population. This study presented a case study of SCA13, where the patient exhibited clinical symptoms of epilepsy and ataxia. The confirmation of the diagnosis was done through Whole Exome Sequncing. CASE PRESENTATION: Since childhood, the seventeen-year-old patient has not been capable of participating in numerous sporting activities and has experienced multiple episodes of unconsciousness within the last two years. The neurological evaluation showed a lack of coordination in the lower limbs. Cerebellar atrophy was detected through brain magnetic resonance imaging (MRI). The patient's gene detection results showed that they exhibit a heterozygous c.1268G > A mutation in the KCNC3 gene located at chr19:50826942. Antiepileptic treatment was promptly administered to the patient, and as a result, her epileptic seizures were resolved quickly. She has since remained free of seizures. After a one-year follow-up, there was no apparent improvement in the patient's health status except seizure free, which may have worsened. CONCLUSION: The case study highlights the importance of actively combining cranial MRI with genetic detection in patients with ataxia of no known cause, particularly in children and young patients, to establish an possibly obvious detection. Patients who are young and have ataxia that is first accompanied by extrapyramidal and epilepsy syndromes should be aware of the potential of having SCA13.

Structured illumination phase and fluorescence microscopy for bioimaging.

This study presents a dual-modality microscopic imaging approach that combines quantitative phase microscopy and fluorescence microscopy based on structured illumination (SI) to provide structural and functional information for the same sample. As the first imaging modality, structured illumination digital holographic microscopy (SI-DHM) is implemented along the transmission beam path. SI-DHM acts as a label-free, noninvasive approach and provides high-contrast and quantitative phase images utilizing the refractive index contrast of the inner structures of samples against the background. As the second imaging modality, structured illumination (fluorescence) microscopy (SIM) is constructed along the reflection beam path. SIM utilizes fluorescent labeling and provides super-resolution images for specific functional structures of samples. We first experimentally demonstrated phase imaging of SI-DHM on rice leaves and fluorescence (SIM) imaging on mouse kidney sections. Then, we demonstrated dual-modality imaging of biological samples, using DHM to acquire the overall cell morphology and SIM to obtain specific functional structures. These results prove that the proposed technique is of great importance in biomedical studies, such as providing insight into cell physiology by visualizing and quantifying subcellular structures.

Multi-harmonic structured illumination-based optical diffraction tomography.

Imaging speed and spatial resolution are key factors in optical diffraction tomography (ODT), while they are mutually exclusive in 3D refractive index imaging. This paper presents a multi-harmonic structured illumination-based optical diffraction tomography (MHSI-ODT) to acquire 3D refractive index (RI) maps of transparent samples. MHSI-ODT utilizes a digital micromirror device (DMD) to generate structured illumination containing multiple harmonics. For each structured illumination orientation, four spherical spectral crowns are solved from five phase-shifted holograms, meaning that the acquisition of each spectral crown costs 1.25 raw images. Compared to conventional SI-ODT, which retrieves two spectral crowns from three phase-shifted raw images, MHSI-ODT enhances the imaging speed by 16.7% in 3D RI imaging. Meanwhile, MHSI-ODT exploits both the 1st-order and the 2nd-order harmonics; therefore, it has a better intensity utilization of structured illumination. We demonstrated the performance of MHSI-ODT by rendering the 3D RI distributions of 5 µm polystyrene (PS) microspheres and biological samples.

Separable Reversible Data Hiding in Encrypted Images for Remote Sensing Images.

High security and effectiveness are critical performance metrics in the data transmission process for satellite remote sensing images, medical images, and so on. Previously, the receiver could gain a high-quality cover image (lossy) after decryption in a separable manner to balance embedding capacity (EC) and security. Completely separable, reversible data hiding in encrypted image (SRDH-EI) algorithms are proposed to address this issue. In this study, the cover image was preprocessed at the sender's end. The pre-embedded pixels and most significant bits (MSB) were compressed via two coding methods to reserve space. Additionally, the header data were embedded for marking. Finally, auxiliary data and secret data were embedded in a forward "Z" and reverse "Z" shape before and after encryption, respectively. The receiver could extract secret data and decrypt the cover image separately using the keys and markers. The experimental results demonstrate that the algorithm reached a high EC for remote sensing images by utilizing pixel correlation at multiple positions within the groups. The cover image could maintain its entropy during the data embedding process, ensuring security. The decrypted image could be recovered without distortion, furthermore, the receiver could achieve complete separability, so it has good application prospects for remote sensing images.

Structural characterization of an L-fuculose-1-phosphate aldolase from Klebsiella pneumoniae.

Fuculose phosphate aldolases play an important role in glycolysis and gluconeogenesis pathways. L-fuculose 1-phosphate aldolase catalyzes the reversible cleavage of L-fuculose 1-phosphate to DHAP and L-lactaldehyde. Class II aldolases found in bacteria are linked to pathogenesis of human pathogens, and have potential applications in the biosynthesis of carbohydrates and other chiral compounds. Here we report the structure of a putative L-fuculose 1-phosphate aldolase (KpFucA) from the nosocomial pathogen Klebsiella pneumoniae to 1.85 Å resolution. The enzyme crystallizes in space group P422 with one monomer per asymmetric unit. Analytical ultracentrifugation analysis confirms that KpFucA is a tetramer in solution. A magnesium ion cofactor and sulfate ion were identified in the active pocket. Enzyme activity assays confirmed that KpFcuA has a strong preference for L-fuculose 1-phosphate as a substrate, but can also catalyze the cleavage of fructose-1,6-bisphosphate and glucose-6-phosphate. This work should provide a starting point for further investigation of the role of KpFucA in K. pneumoniae pathogenesis or in industrial applications.

Structural characterization of the novel stress response facilitator (SrfA) from Pseudomonas aeruginosa.

Chronic pulmonary infections in those living with cystic fibrosis or chronic obstructive pulmonary disease are promoted by production of alginate by the opportunistic pathogen Pseudomonas aeruginosa. Alginate biosynthesis enzymes in P. aeruginosa are regulated by the extracytoplasmic function alternative sigma factor σ22 either by mutation in mucA or in response to envelope stress. An intergenic region between ORFs PA2559 and PA2560 in P. aeruginosa is σ22-dependent and its transcription is activated by cell wall stress. This stress-responsive transcript encodes a novel stress response facilitator, SrfA, that is exclusively conserved only in P. aeruginosa species. Here we report the first three-dimensional structure of SrfA determined by molecular replacement using fold prediction to generate a search model. The SrfA structure adopts a helix-loop-helix fold that shares some similarity with structures of anti-activator or effector proteins. A ΔsrfA mutant strain of P. aeruginosa PAO1 exhibited significantly reduced biofilm formation, which was restored to wild-type levels when ΔsrfA was complemented with srfA. The ΔsrfA strain also exhibited increased sensitivity to macrolide antibiotics. We further show using MicroScale Thermophoresis that SrfA interacts with both PA2559 and PA2560 with high affinity. This work provides a starting point for further investigation into the role of SrfA in response to cell wall stress.

Genome-wide association study identifies variants of GhSAD1 conferring cold tolerance in cotton.

Cold stress is a major environmental factor affecting plant growth and development. Although some plants have developed resistance to cold stress, the molecular mechanisms underlying this process are poorly understood. Using genome-wide association mapping with 200 cotton accessions collected from different regions, we identified variations in the short chain alcohol dehydrogenase gene, GhSAD1, that responds to cold stress. Virus-induced gene silencing and overexpression in Arabidopsis revealed that GhSAD1 fulfils important roles in cold stress responses. Ectopic expression of a haploid genotype of GhSAD1 (GhSAD1HapB) in Arabidopsis increased cold tolerance. Silencing of GhSAD1HapB resulted in a decrease in abscisic acid (ABA) content. Conversely, overexpression of GhSAD1HapB increased ABA content. GhSAD1HapB regulates cold stress responses in cotton through modulation of C-repeat binding factor activity, which regulates ABA signalling. GhSAD1HapB induces the expression of COLD-REGULATED (COR) genes and increases the amount of metabolites associated with cold stress tolerance. Overexpression of GhSAD1HapB partially complements the phenotype of the Arabidopsis ABA2 mutant, aba2-1. Collectively, these findings increase our understanding of the mechanisms underlying GhSAD1-mediated cold stress responses in cotton.

Genome-wide association study reveals that GhTRL1 and GhPIN8 affect cotton root development.

KEY MESSAGE: Two regions located at chromosome A05 and D04 were found to be significantly associated with 0-0.5 mm and 0.5-2 mm diameter roots, respectively, and two candidate genes related to root development were identified. Roots absorb water and nutrients, and play an important role in plant growth. However, there are few genetic developmental studies on cotton root structural traits. In this study, we used 200 upland cotton (Gossypium hirsutum L.) varieties to analyze the phenotypic variation of 43 traits. A total of 2001 related single-nucleotide polymorphism (SNP) sites located within or near 1046 genes were detected through a genome-wide association study (GWAS). The 32 root traits were linked to SNPs that corresponded to 317 nonrepetitive genes. For SNPs associated with root length and 0-0.5 mm diameter root traits, a significant peak appeared on chromosome A05 (between 21.91 and 22.24 Mb). For SNPs associated with root surface area, root volume and 0.5-2 mm diameter root traits, a significant peak appeared on chromosome D04 (between 7.35 and 7.70 Mb). Within these two key regions, SNPs were detected in the promoter and coding regions of two candidate genes, GhTRL1-A05 and GhPIN8-D04. The expression levels of these two genes also changed significantly according to transcriptome sequencing and quantitative real-time PCR (qRT-PCR). After silencing the GhTRL1 and GhPIN8 genes via virus-induced gene silencing (VIGS), we found that the plants expressing TRV2::GhTRL1 and TRV2::GhPIN8 had a reduced root length, surface area. Moreover, the contents of cis-12-oxo-phytodienoic acid (cis-OPDA), isopentenyl adenosine (iPR) and cis-zeatin (cZ) in the roots of the plants expressing TRV2::GhTRL1 decreased. This study contributes to the cultivation and improvement of cotton varieties.

Incidence and Risk Factors Associated with Technique Failure in the First Year of Peritoneal Dialysis: A Single Center Retrospective Cohort Study in Southern China.

BACKGROUND: Technique failure is more likely to occur during the first 12 months after peritoneal dialysis (PD) initiation, which is a great challenge encountered in PD patients. The aim of this study was to investigate the incidence and risk factors associated with technique failure within the first year of PD patients in Southern China. METHODS: Incident PD patients who were followed up for at least one year at The First Affiliated Hospital of Sun Yat-sen University from January 1, 2006 to December 31, 2015 were included. Technique failure was defined as transferring to hemodialysis (HD) for more than 30 days or death within the first year after start of PD. A competitive risk regression analysis was used to explore the incidence and risk factors of the technique failure. RESULTS: Overall, 2,290 incident PD patients were included in this study, with a mean age of 48.2 ± 15.7 years, 40.9% female and 25.2% with diabetes. A total of 173 patients (7.5%) had technique failure during the first year of PD. Among them, the patient death account for 62.4% (n = 108) and transferring to HD account for 37.6% (n = 65). The main reasons for death were cardiovascular diseases (n = 32, 29.6%), infection (n = 15, 13.8%) and for conversion to HD were mechanical cause (n = 28, 43.1%), infection cause (n = 22, 33.8%). The risk factors for the technique failure included advanced age (HR 2.78, 95%CI 1.82-4.30), low body mass index (BMI < 18.5 kg/m2: HR 1.77, 95%CI 1.17-2.67), history of congestive heart failure (HR 2.81, 95%CI 1.58-4.98), or time on HD before PD ≤ 3 months (HR 1.49, 95%CI 1.05-2.10), peritonitis (HR 2.02, 95%CI 1.36-3.01);while higher serum albumin (HR 0.93, 95%CI 0.89-0.96) and using employee medical insurance to pay expenses (HR 0.47, 95%CI 0.32-0.69) were associated with reduced risk. CONCLUSIONS: Advanced age, poor nutritional status, history of HD or congestive heart failure, and peritonitis are related factors that increase the risk of technique failure in the first year of PD, while patients' type of medical insurance may also have an influence on early technique failure.

The efficacy and safety of intravenous tirofiban in the treatment of acute ischemic stroke patients with early neurological deterioration.

WHAT IS KNOWN AND OBJECTIVE: Many patients with acute ischemic stroke (AIS) develop early neurological deterioration (END), leading to disabilities or death. Thus, this study aimed to investigate the efficacy and safety of intravenous tirofiban in treating patients with AIS and END who missed the thrombolysis time window. METHODS: A total of 123 AIS-END patients participated in the study between January 2021 and December 2021. Patients were randomized into the tirofiban group (n = 63) and the control group (n = 60) based on whether a tirofiban injection was administered. The National Institute of Health Stroke Scale (NIHSS) was used to assess neurological function at the 48th hour and on the 7th day after intervention, and the modified Rankin Scale (mRS) was used to assess neurological recovery 90 days after AIS. Adverse reactions during the intervention were recorded for safety analysis. RESULTS AND DISCUSSION: The 7th day NIHSS and 90th day post-AIS mRS scores of the tirofiban group were significantly lower than those of the control group (p < 0.05), while the 90th day good prognosis (mRS ≤ 2) rate of the tirofiban group was significantly higher (84.13% vs. 65.00%, p < 0.05). Logistic regression demonstrated a protective effect of tirofiban for good prognosis in AIS patients with END (OR = 4.675, 95% CI [1.012-21.605], p < 0.05). No cases of intracranial haemorrhage transformation or death were observed during the treatment in either group. WHAT IS NEW AND CONCLUSION: Tirofiban injection exhibited a high safety profile and significantly improved the prognosis of AIS-END patients who missed the intravenous thrombolysis time window.