PubMed Health⌕ Search

Biomedical subjects

Kai Zhang

Publications and source records attributed to Kai Zhang.

At least 19 recordsLinked to original sources
PubMed2026

The complete chloroplast genome of Heterostemma pingtaoi (Apocynaceae).

Heterostemma pingtaoi, a species endemic to Hainan Island, China, was discovered and formally described in the family Apocynaceae in 2010. However, genetic and evolutionary information on the genus Heterostemma remains poorly understood. Here, we report the complete chloroplast (cp) genome sequence of H. pingtaoi. The genome displays the typical quadripartite structure characteristic of dicotyledonous plant cp genomes, with a total length of 162,681 bp and a GC content of 38.25%. The cp genome encodes 131 genes, including 84 protein-coding genes, 8 rRNA genes, and 39 tRNA genes. Phylogenetic analysis based on the complete cp genome sequences confirmed that the genus Heterostemma forms a monophyletic group at the base of tribe Ceropegieae (Apocynaceae), with 100% bootstrap support. This study provides essential genomic resources for future taxonomic and evolutionary studies of Heterostemma species.

Apocynaceae↗
PubMed2026

Enhancing pan-cancer spatial transcriptomics at single-cell resolution with stPainter.

Subcellular spatial transcriptomics can resolve tissue architecture at cellular scale, but sparse gene panels and limited detection sensitivity constrain downstream analysis. Existing enhancement methods often require tissue-matched single-cell RNA sequencing (scRNA-seq) references and dataset-specific retraining. Here we show that stPainter, a conditional generative model pretrained on a pan-cancer scRNA-seq atlas, can enhance spatial transcriptomics data without matched references or retraining. Using a latent diffusion architecture guided by Stochastic Differential Equations (SDE), stPainter reconstructs expanded expression profiles from sparse measurements and produces latent representations for clustering and cell-state analysis. When we apply stPainter upon 6 spatial transcriptomics datasets of different cancer types, we demonstrate that our model empowers downstream biological analyses, including fine-grained subpopulation clustering and pathway enrichment. Comparison with spatially resolved proteomics (CODEX) provided independent support for regional agreement between imputed cellular compositions and protein-level tissue organization. These results establish stPainter as a scalable approach for analyzing tumor microenvironments without auxiliary sequencing data.

Spatial Transcriptomics↗
PubMed2026

The effect of dexmedetomidine in mechanically ventilated patients with sepsis and septic shock: a meta-analysis of randomized controlled trials.

PURPOSE: Dexmedetomidine (DEX) is a central sympatholytic with sedative properties widely used in critically ill patients. However, its effects in patients with sepsis and septic shock remain controversial. This meta-analysis evaluated the efficacy and safety of DEX compared to other sedatives in mechanically ventilated patients with sepsis and septic shock. METHODS: A systematic search was conducted across PubMed, Embase, Scopus, and Cochrane Library from inception through May 1, 2025 for randomized controlled trials comparing DEX with other sedatives or placebo in mechanically ventilated patients with sepsis and septic shock. Primary outcomes included overall mortality and Sequential Organ Failure Assessment (SOFA) scores. Secondary outcomes encompassed duration of mechanical ventilation (MV), length of stay in Intensive Care Unit (ICU), incidence of hypotension and bradycardia. RESULTS: Fifteen studies involving 3,882 patients (1,945 in the DEX group, 1,937 in the control group) were included. DEX was demonstrated no significant differences compared to other sedatives or placebo in overall mortality (Risk Ratio [RR] 0.98, 95% Confidence Interval [CI] 0.90 to 1.07, p = 0.71, I2 = 0%), SOFA scores (Mean Difference [MD] - 0.14, 95% CI -0.81 to 0.52, p = 0.67, I2 = 0%), length of stay in ICU (MD -0.32, 95% CI -1.69 to 1.06, p = 0.65, I2 = 77%), or incidence of hypotension (RR 1.15, 95% CI 0.81 to 1.62, p = 0.44, I2 = 14%). However, DEX significantly reduced the duration of MV (MD -0.54, 95% CI -0.98 to -0.10, p = 0.02, I2 = 25%) but was associated with an increased incidence of bradycardia (RR 1.67, 95% CI 1.22 to 2.28, p = 0.001, I2 = 0%). CONCLUSIONS: In mechanically ventilated patients with sepsis and septic shock, DEX shortened duration of MV but was associated increased bradycardia risk. No mortality or organ dysfunction benefits were observed. These findings suggest DEX is a reasonable therapeutic option to facilitate earlier ventilator weaning in selected patients (particularly those without shock), but careful monitoring for cardiovascular adverse effects is warranted.

Humans↗
PubMed2026

Mitochondrial retrograde signal through GCN5L1 transition-mediated PPARγ stabilization promotes MASLD development.

Mitochondrial retrograde signaling plays crucial roles in maintaining metabolic homeostasis via regulating genome modification and oxidative responsive gene expression. In this study, we identified GCN5L1, a protein localized in both mitochondria and cytoplasm, and demonstrated its specific translocation from mitochondria to cytoplasm during lipid overload and high-fat diet feeding. Using transcriptome and proteome analyses, we identified that cytoplasmic GCN5L1 binds to and promotes the acetylation of PPARγ at lysine 289 (K289). This acetylation protected PPARγ from ubiquitination-mediated degradation by proteasome. GCN5L1 translocation enhanced protein stability of PPARγ and subsequently promoted lipid accumulation in both cultured cells and murine models. Our study further reveals that PPARγ-K289 mutation reduces the ubiquitination of PPARγ and exacerbates liver steatosis in mice. These findings unveil a mitochondrial retrograde signaling during lipid overload, which regulates the crucial lipogenic transcriptional factor. This discovery elucidates an unrecognized mitochondrial function and mechanism underlying hepatic lipid synthesis.

Animals↗
PubMed2026

Phosphoproteomics identification of ERK-dependent activation of Rps6kb1 in cardiac hypertrophy.

Cardiomyocyte growth is tightly controlled by multiple signaling pathways. Identification of master kinases in this process is essential in exploring potential targets for the treatment of pathological cardiac hypertrophy and heart failure. Here we identified the mTOR-independent activation of ribosomal protein S6 kinase b1 (Rps6kb1) during cardiomyocyte growth. By utilizing phosphoproteomics in primary neonatal rat ventricular myocytes, we revealed Rps6kb1 as one of most activated kinases under growth stimulation. We further demonstrated the role of Rps6kb1 phosphorylation in pathological cardiac hypertrophy and heart failure. We showed that the phosphorylation of multiple sites in Rps6kb1, including T367 in the kinase domain and S418/T421/S424 in the C-terminal domain, is not directly regulated by the activity of mTOR but coupled with the activation of the MEK1/ERK axis. In mice, cardiomyocyte-specific deletion of Rps6kb1 significantly inhibited both constitutively active ERK- and pressure overload-induced cardiac hypertrophy. In contrast, cardiomyocyte-specific overexpression of wild-type Rps6kb1, rather than the phosphorylation-defective mutant, elevated cardiac hypertrophy and augmented pressure overload-induced heart failure. In conclusion, our findings reveal that the MEK/ERK axis primes Rps6kb1 activation through phosphorylation of 2 separate domains of Rps6kb1, which may play an essential role in cardiac hypertrophy and heart failure under hemodynamic stress.

Animals↗
PubMed2025

The cytokine CSBF inhibits the IL-17A and TNF-α inflammatory pathways via SUSD2-ACT1 in keratinocytes and alleviates IMQ-induced psoriasis.

Overactivation of inflammatory signaling in keratinocytes is critical for psoriatic skin inflammation, but its regulatory mechanisms remain incompletely understood. Here, we demonstrate that the cytokine CSBF inhibits both individual and synergistic proinflammatory signaling induced by IL-17A and TNF-α (IL-17A/TNF-α) in keratinocytes, playing a protective role in psoriatic inflammation. The expression of CSBF was increased in the skin lesions and serum of psoriatic patients, and IL-17A/TNF-α enhanced its production. Csbf deletion exacerbated IMQ-induced psoriasis-like skin inflammation and led to hyperactivation of IL-17A/TNF-α signaling in keratinocytes. The CSBF protein significantly ameliorated psoriatic manifestations and suppressed IL-17A/TNF-α signaling through the receptor SUSD2. Mechanistically, CSBF-SUSD2 competed with TRAF6 and TNFR1 for interaction with ACT1, inhibiting the IL-17A/TNF-α signaling pathway. Overall, the anti-inflammatory cytokine CSBF has the potential to be a therapeutic option for psoriasis by targeting keratinocytes.

Psoriasis↗
PubMed2025

A telomere-to-telomere gap-free genome assembly of the endangered humphead wrasse (Cheilinus undulatus).

Humphead wrasse, Cheilinus undulatus, is an endangered fish species with high economic and ecological value as well as natural sex change from female to male, while sexual selection occurs in breeding aggregations. In our present study, we constructed the first gap-free telomere-to-telomere (T2T) genome assembly for humphead wrasse, by integration of PacBio HiFi, ONT Ultra-long and Hi-C sequencing techniques. With 99% of the entire sequences anchored into 24 chromosomes, this haplotypic genome assembly spans approximately 1.25 Gb and presents a complete set of 48 telomeres and 24 centromeres. In terms of correctness (quality value QV: 53.447) and completeness (BUSCO score: 99.3%), this chromosome-scale assembly is indeed of high quality. We predicted 658.03 Mb of repetitive sequences and annotated 26,609 protein-coding genes in the assembled genome. This high-quality T2T genome assembly not only facilitates the genetic conservation of humphead wrasse, but also offers fundamental genomic data for supporting in-depth investigations on functional genomics, genetic diversity, and selective breeding for this economically important teleost.

Animals↗
PubMed2007

[p38 MAPK/cPLA2 pathway mediates interleukins release in inflammatory cell model].

OBJECTIVE: To explore the underlying mechanism of lipopolysaccharide (LPS)-induced interleukin-1 beta (IL-1 beta) and IL-6 release via p38 mitogen-activated protein kinase (MAPK) pathway in HeLa cells for further identification of involved down-stream message factors. METHODS: HeLa cells were challenged with LPS to reproduce inflammatory cell model. The activity or expression of p38 MAPK, cytosolic phospholipase A(2) (cPLA(2)) and COX-2, was inhibited with pretreatment of inflammatory HeLa cells with the inhibitors (SB203580, AACOCF(3), NS-398) or transfected with the cPLA(2) antisense oligonucleotide (SK7111), then the activities and/or expression of p38 MAPK, cPLA(2), COX-2, and relationship with levels of IL-1 beta and IL-6 supernatants were determined in each group. RESULTS: SB203580 obviously down-regulated the activities of p38 and cPLA(2), as well as the release of IL-1 beta and IL-6. AACOCF(3) and SK7111 blocked dose-dependently the activity or expression of cPLA(2), IL-1 beta and IL-6 production. However, the expression of COX-2 could hardly be detected in HeLa cells, even after LPS treatment. At the same time, pre-treatment with NS-398 had no effect on IL-1 beta, IL-6 production. CONCLUSION: p38 MAPK/cPLA(2) pathway mediates the expression of IL-1 beta and IL-6 resulting from LPS treatment of HeLa cells, while COX-2, as a down-stream enzyme of cPLA(2) has no effect in this process.

Cyclooxygenase 2↗
PubMed2006

Deep brain stimulation in the treatment of secondary dystonia.

BACKGROUND: Dystonia is one of the most challenging movement disorders to treat. Medications and surgeries are the two methods to control dystonic symptoms. For patients with dystonia in whom symptoms are inadequately controlled with pharmacologic measures, the use of deep brain stimulation (DBS) can improve symptoms and enhance functional capacity. The best candidate for DBS is believed to be primary generalized dystonia, especially the DYT-1 type. Here, we report 9 cases of secondary dystonia to explore the feasibility, indications and complications of DBS in the treatment of secondary dystonia. METHODS: From July 2003 to June 2006, nine patients with secondary dystonia underwent surgery at Beijing Tiantan Hospital. Among them, 2 were diagnosed as having tardive dystonia, 1 had posttraumatic dystonia, 3 had a history of perinatal anoxia, 1 had neonatal pathologic jaundice, and 2 had no exact contributory history; MRI showed bilateral lentiform nuclei degeneration in one patient. Six patients underwent bilateral subthalamic nucleus (STN)-DBS, two underwent unilateral STN-DBS, the other underwent left STN and right globus pallidus internus (GPi)-DBS. RESULTS: With intraoperative microelectrode recording, the targeted nucleus was accurately localized. Tentative stimulation could decrease muscle tension to the same extent, but twisting was not obviously improved. Follow-up for 3 months to 3 years showed satisfactory results in 3 patients with tardive dystonia and posttraumatic dystonia and that Burke-Fahn-Marsden Dystonia Scale (BFMS) decreased by more than 90%. The improvement of symptoms was progressive along with time. The other 6 patients had slight to moderate improvement. None of them had severe surgery-related complications. One had lead fracture 16 months after surgery and the lead was then evacuated. CONCLUSIONS: DBS could be an ideal treatment for patients with tardive and posttraumatic dystonia. For patients with perinatal anoxia and diffuse impairment in the basal ganglia, DBS seemed not to be a good choice. STN could be an ideal target. Intraoperative microelectrode recording and mild amelioration of muscle tension are indicators of correct target location. No severe complications occurred.

Adolescent↗
PubMed2006

A bifunctional monolithic column for combined protein preconcentration and digestion for high throughput proteomics research.

Enzymatic digestion of proteins is a key step in protein identification by mass spectrometry (MS). Traditional solution-based protein digestion methods require long incubation times and are limitations for high throughput proteomics research. Recently, solid phase digestion (e.g. trypsin immobilization on solid supports) has become a useful strategy to accelerate the speed of protein digestion and eliminate autodigestion by immobilizing and isolating the enzyme moieties on solid supports. Monolithic media is an attractive support for immobilization of enzymes due to its unique properties that include fast mass transfer, stability in most solvents, and versatility of functional groups on the surfaces of monoliths. We prepared immobilized trypsin monolithic capillaries for on-column protein digestion, analyzed the digested peptides through LC/FTICR tandem MS, and compared peptide mass fingerprinting by MALDI-TOF-MS. To further improve the digestion efficiency for low abundance proteins, we introduced C4 functional groups onto the monolith surfaces to combine on-column protein enrichment and digestion. Compared with immobilized trypsin monolithic capillaries without C4, the immobilized trypsin-C4 monolith showed improved digestion efficiency. A mechanism for increased efficiency from the combination of sample enrichment and on-column digestion is also proposed in this paper. Moreover, we investigated the effects of organic solvent on digestion and detection by comparing the observed digested peptide sequences. Our data demonstrated that all columns showed good tolerance to organic solvents and maintained reproducible enzymatic activity for at least 30 days.

Animals↗
PubMed2006

Effects of carvedilol on transient outward and ultra-rapid delayed rectifier potassium currents in human atrial myocytes.

Carvedilol is a beta- and alpha(1)-adrenoceptor antagonist. It is widely used in the treatment of cardiovascular diseases including atrial arrhythmias. However, it is unclear whether carvedilol may affect the repolarization currents, transient outward K(+) current (I(to)) and ultra-rapid delayed rectifier K(+) current (I(Kur)) in the human atrium. The present study evaluated effects of carvedilol on I(to) and I(Kur) in isolated human atrial myocytes by whole-cell patch-clamp recording technique. We found that carvedilol reversibly inhibited I(to) and I(Kur) in a concentration-dependent manner. Carvedilol (0.3 microM) suppressed I(to) from 9.2+/-0.5 pA/pF to 4.8+/-0.5 pA/pF (P<0.01) and I(Kur) from 3.6+/-0.5 pA/pF to 1.9+/-0.3 pA/pF (P<0.01) at +50 mV. I(to) was inhibited in a voltage-dependent manner, being significantly attenuated at test potentials from +10 to +50 mV, whereas the inhibition of I(Kur) was independent. The concentration giving a 50% inhibition was 0.50 microM for I(to) and 0.39 microM for I(Kur). Voltage-dependence of activation, inactivation and time-dependent recovery from inactivation of I(to) were not altered by carvedilol. However, time to peak and time-dependent inactivation of I(to) were significantly accelerated, indicating an open channel blocking action. The findings indicate that carvedilol significantly inhibits the major repolarization K(+) currents I(to) and I(Kur) in human atrial myocytes.

Adrenergic alpha-Antagonists↗
PubMed2006

Aberrant methylation of the 8p22 tumor suppressor gene DLC1 in renal cell carcinoma.

Epigenetic mechanisms involving DNA methylation and chromatin remodeling are important in silencing tumor suppressor genes (TSG) in various malignancies, including renal cell carcinoma (RCC). DLC1 (deleted in liver cancer 1)/ARHGAP7 is a recently identified 8p22 candidate TSG. Frequent methylation of the DLC1 promoter with resultant gene silencing has been reported in several tumors, but not in RCC yet. We examined DLC1 promoter methylation in 34 primary RCCs and the corresponding non-malignant tissues, and the correlation of DLC1 methylation with the clinicopathological characteristics of RCC patients. Although DLC1 methylation and downregulation were only detected in one of seven RCC cell lines using methylation-specific PCR (MSP) and semi-quantitative reverse-transcription PCR, we found that the DLC1 promoter was methylated in 35% (12/34) of primary RCC tumors, which was further confirmed by direct sequencing of MSP products and high-resolution bisulfite genomic sequencing. In contrast, only one of the 34 (3%) non-malignant renal tissues had weak methylation. Aberrant DLC1 methylation appeared to be a relatively early event during renal tumorigenesis since 33% of the RCC tumors with pT1 (TNM staging) showed methylation, which is similar to other late stage tumors. Thus, our results demonstrated that DLC1 methylation occurs in a subset of RCC tumors and may play a role in renal carcinogenesis.

Adult↗
PubMed2006

Sensitization of surfactants on the chemiluminescence reaction of fluorescein isothiocyanate labeled proteins.

The effect of surfactants on fluorescein isothiocyanate (FITC)-bovine serum albumin (BSA)-hypochlorite (ClO(-)), FITC-human serum albumin (HSA)-ClO(-), FITC-ovoconalbumin (OVA)-ClO(-), FITC-hemoglobin (Hb)-ClO(-) systems were investigated with chemiluminescence method by the reversed phase flow injection. It was found that the chemiluminescence (CL) intensity of each system was increased greatly in the presence of cationic surfactants. Cethyltrimethylammonium bromide (CTAB) is the optimal surfactant of these systems. The optimal conditions of the CL reaction and the optimal concentration of CTAB were examined and the function of cationic surfactant CTAB on the CL reaction was also discussed.

Animals↗
PubMed2006

Measurement error of lumbar total disc replacement range of motion.

STUDY DESIGN: A retrospective review of lumbar total disc replacement (TDR) radiographs. OBJECTIVE: To determine the error and variability in measuring TDR radiographic range of motion (ROM). SUMMARY OF BACKGROUND DATA: Motion preservation is the driving force behind lumbar TDR technology. In the recent literature, sagittal radiographic TDR ROM as low as 2 degrees has been reported. In these studies, ROM was determined by using the Cobb method to measure TDR sagittal alignment angles in flexion-extension lateral radiographs. However, previous studies in the spinal deformity literature have shown that the Cobb method is very susceptible to measurement error. METHODS: There were 5 observers, including 2 attending orthopedic spine surgeons, 1 spine fellow, 1 fifth-year resident, and 1 fourth-year resident, who measured the ROM of 50 ProDisc II (Synthes Spine Solutions, New York, NY) TDRs on standard flexion-extension lumbar spine radiograph sets. Repeated measurements were made on 2 occasions using the Cobb method. Measurement variability was calculated using 3 statistical methods. RESULTS: The 3 statistical methods resulted in extremely similar values for TDR ROM observer variability. Overall, the intraobserver variability of TDR ROM measurement was +/-4.6 degrees, and interobserver variability was +/-5.2 degrees . CONCLUSIONS: To be 95% certain that an implanted TDR prosthesis has any sagittal motion, a ROM of at least 4.6 degrees must be observed, which is the upper limit of intraobserver measurement variability for a TDR with a true ROM of 0 degrees. To be 95% certain that a change in TDR ROM has occurred between 2 measurements by the same observer, a change in ROM of at least 9.6 degrees must be observed (the entire range of +/-4.6 degrees intraobserver variability). ROM measurement variability should be considered when evaluating the success or failure of motion preservation in lumbar TDR.

Adult↗
PubMed2006

Incorporation of a flared inlet capillary tube on a fourier transform ion cyclotron resonance mass spectrometer.

Flared inlet capillary tubes have been coupled with a Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometer to help the ion transmission from the atmospheric pressure to the first vacuum region. We investigated different types of atmospheric pressure ionization methods using flared inlet tubes. For most of the ionization methods, such as ESI and DESI, increased ion current transmitted from the atmospheric pressure ion source to the first stage vacuum system was observed with the use of our enhanced ion inlet designs. The corresponding ion intensity detected on a FT-ICR mass spectrometer was also observed to increase two- to fivefold using ESI or DESI with the flared tube inlet. Moreover, increased spray tip positional tolerance was observed with implementation of the flared inlet tube. We also include our preliminary results obtained by coupling AP-MALDI with flared inlet tube in this paper. For AP-MALDI, the measured ion current transferred through the flared inlet tube was about 2 to 3 times larger than the ion current through the control non-flared inlet tube.

Angiotensins↗
PubMed2006

Clinicians and the governance of hospitals: a cross-cultural perspective on relations between profession and management.

This paper explores similarities and differences in the value stances of clinicians and hospital managers in Australia, England, New Zealand and China, and provides some new insights into how we theorise about the health profession and its relations with management. The paper draws on data derived from a closed-ended questionnaire administered to 2637 hospital-based medical, nursing and managerial staff. We examine variations between the countries in the value orientations of doctors, nurses and managers by considering their assessments of issues that are the focus of reform. In particular, we examine the ways in which the Chinese findings differ from those of the other countries. Whereas the results from the Commonwealth hospitals showed a marked division between clinicians and managers about issues that can affect clinical autonomy, this was not the case in the Chinese hospitals. The concluding discussion traces these differences to a number of cultural, organisational and policy-based factors. The implications of our findings on how we conceive the relationship between professionals and organisations are then discussed, as are further lines of research.

Analysis of Variance↗
PubMed2006

Three-dimensional chiral imaging by sum-frequency generation.

A sum-frequency generation (SFG) microscope that is sensitive toward molecular chirality was demonstrated for the first time. Optically active images of chiral 1,1'-bi-2-naphthol solutions were obtained with submicron spatial resolution. Three-dimensional sectioning capability of our microscope was also demonstrated. This optically active SFG microscopy can potentially become a powerful imaging technique for biological samples.

Image Processing, Computer-Assisted↗