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Ping Hu

Publications and source records attributed to Ping Hu.

At least 19 recordsLinked to original sources
PubMed2026

Looked but didn't see: inattentional blindness and yes-bias confabulation in vision-language models.

Previous work showed that many participants fail to notice a gorilla in a video of people playing basketball. Another study found that 83% of trained radiologists failed to report a gorilla figure inserted into a chest CT nodule-search task, even though eye-tracking revealed that most observers had foveated the figure. We ask whether a similar phenomenon exists in contemporary vision-language models (VLMs). We find that (i) VLMs are capable of spotting the gorilla in both still-frame images and videos of lung CT scans; (ii) models display inattentional blindness, which varies according to model generation and type of stimulus presented; (iii) Gemini-3.1-Pro outperforms most other flagship and open-weight VLMs at identifying the presence or absence of the gorilla. We additionally ran a segmentation experiment utilizing two different model classes: a generalist (SAM 3), which found the gorilla but produced little to no results for anatomy-based prompts; a medical specialist (BiomedParse), which produced more promising anatomy-based results but flagged "gorilla" on gorilla-free control videos on 82% of frames. The behavioral signature of inattentional blindness reproduces in VLMs, but a unique confabulation failure mode means that any "did the model see X" claim requires signal-detection analysis with a matched-control false-alarm baseline.

Journal Article↗
PubMed2025

SUG2 controls grain size and weight by influencing GS2 transcription level in rice.

Grain size is a critical yield determinant and a complex quantitative trait in rice. The major quantitative trait locus GS2, which encodes the transcriptional regulator OsGRF4, has been characterized as a key controller of grain size and grain weight in rice. Building upon existing germplasm resources, exploring the upstream and downstream genes of known grain size regulators is an effective approach to gradually refine and expand the molecular regulatory network underlying grain size. Here, we report that a suppressor of the gain-of-function allele GS2AA, SUG2, which encodes an importin β nuclear transport protein. Phenotypic characterization reveals that the sug2 GS2AA mutant exhibits small grains by inhibiting cell expansion in the spikelet hull. Protein interaction analyses demonstrate that SUG2 physically interacts with GS2 both in vivo and in vitro, and the SUG2A mutation reduces SUG2 expression levels and inhibits GS2 transcriptional activation activity, resulting in decreased GS2 expression levels and GS2 protein abundance in sug2 GS2AA. Genetic analyses indicate that SUG2 and GS2 may be partially involved in a common pathway regulating grain size and weight in rice. These findings elucidate the grain size regulatory relationship between SUG2 and GS2 and provide novel insights into the precision breeding of yield optimization in rice.

Oryza↗
PubMed2006

Immune cell involvement in dorsal root ganglia and spinal cord after chronic constriction or transection of the rat sciatic nerve.

Chronic constriction injury (CCI) of the sciatic nerve in rodents produces mechanical and thermal hyperalgesia and is a common model of neuropathic pain. Here we compare the inflammatory responses in L4/5 dorsal root ganglia (DRGs) and spinal segments after CCI with those after transection and ligation at the same site. Expression of ATF3 after one week implied that 75% of sensory and 100% of motor neurones had been axotomized after CCI. Macrophage invasion of DRGs and microglial and astrocytic activation in the spinal cord were qualitatively similar but quantitatively distinct between the lesions. The macrophage and glial reactions around neurone somata in DRGs and ventral horn were slightly greater after transection than CCI while, in the dorsal horn, microglial activation (using markers OX-42(for CD11b) and ED1(for CD68)) was greater after CCI. In DRGs, macrophages positive for OX-42(CD11b), CD4, MHC II and ED1(CD68) more frequently formed perineuronal rings beneath the glial sheath of ATF3+ medium to large neurone somata after CCI. There were more invading MHC II+ macrophages lacking OX-42(CD11b)/CD4/ED1(CD68) after transection. MHC I was expressed in DRGs and in spinal sciatic territories to a similar extent after both lesions. CD8+ T-lymphocytes aggregated to a greater extent both in DRGs and the dorsal horn after CCI, but in the ventral horn after transection. This occurred mainly by migration, additional T-cells being recruited only after CCI. Some of these were probably CD4+. It appears that inflammation of the peripheral nerve trunk after CCI triggers an adaptive immune response not seen after axotomy.

Activating Transcription Factor 3↗
PubMed2006

Integrin activation in the heart: a link between electrical and contractile dysfunction?

Integrins mechanically link the cytoskeleton to the extracellular matrix in cardiac myocytes and are thereby involved in mechanotransduction. Integrins appear to be necessary for cardiac myocyte hypertrophy. To determine the effect of increased integrin ligation and signaling on adult cardiac function, a heart-specific truncated alpha(5) integrin (gain of function) was conditionally expressed in mice. Four days later, we observed an 80% reduction in amplitude of the QRS complex, profound systolic dysfunction, decreased connexin43, loss of gap junctions, and abnormal intercalated discs. Surprisingly, isolated left ventricular myocytes contracted normally and exhibited normal Ca(2+) transients. This suggested that cell/cell electrical and/or mechanical coupling was disrupted. To distinguish electrical from mechanical coupling deficits, we compared the papillary muscle force generated by electrically stimulated versus rapid cooling contractions in which intracellular Ca(2+) is released without electrical depolarization. Both were decreased in the transgenic muscle. However, electrically stimulated contractions were more significantly reduced than rapid cooling contractures. This suggests a component of cell/cell electrical uncoupling. Optical mapping revealed a loss of the normal elliptical isochronal activation pattern implying a loss of preferential conduction through gap junctions. For the first time, we have shown that integrins can regulate both mechanical and electrical coupling in the adult heart, even in the absence of primary hemodynamic alterations. Furthermore, we demonstrated that unregulated integrin activation leads to both contractile dysfunction and arrhythmias.

Animals↗
PubMed2006

Geometrical confinements and depletion interactions.

In the system with two large spheres confined between two parallel plates, there are depletion interactions between the two large spheres and between one large sphere and the closely placed plate. Obviously, the depletion interactions exerted on one large sphere will be strongly affected by the presence of the closely placed plate or the other large sphere. This prediction is confirmed by the numerical results obtained through the acceptance ratio method (ARM) or density integration method (DIM), i.e., they are strengthened when two large spheres are contacted. Furthermore, it is found that the influences on the depletion forces are also sensitive to the angle of the centers' connection line between the two large spheres and the confining walls. In addition, the numerical results show that the total depletion force exerted on one large sphere from both the other large sphere and the closely placed plate can be determined through ARM or DIM from the interactions between the two large spheres or between one large sphere and the corresponding closely placed plate.

Journal Article↗
PubMed2006

N-all-trans-retinoyl-L-proline inhibits metastatic potential of hepatocellular carcinoma cells.

Tumor metastasis is usually a serious problem in tumor patients because of the lack of therapeutic approaches. A new compound, N-all-trans-retinoyl-L-proline (ATRP), has been developed and its metastasis inhibition activity has been studied. Low concentrations of ATRP have already been found to inhibit hepatocellular carcinoma cells (HCC) in a dose- and time-dependent manner by inducing the expression of p27(kip). We found that ATRP inhibited metastasis-associated behaviors in Hep3B cells, such as cell migration, invasion, collagen adhesion and gelatinase expression, more significantly than retinoic acid. Further, such inhibitory activities were observed in the regulation of cellular surface fucosylated epitope functions, such as binding of ulex europaeus lectin, expression of Lewis x, y and b, and activity of alpha1,3 fucosyltransferase. Hep3B cells pretreated with ATRP showed a significantly reduced incidence of experimental intrahepatic metastasis in nude mice. We conclude that ATRP is an alternative inhibitor and potential therapeutic agent for HCC metastasis with a different mechanism of action from ATRP.

Animals↗
PubMed2006

A novel cytochrome P450, zebrafish Cyp26D1, is involved in metabolism of all-trans retinoic acid.

Retinoid signaling is essential for development of vertebrate embryos, and its action is mainly through retinoic acid (RA) binding to its RA receptors and retinoid-X receptors, while the critical concentration and localization of RA in embryos are determined by the presence and activity of retinal dehydrogenases (for RA synthesis) and cytochrome P450 RAs (Cyp26s) (for degradation of RA). Previously, we identified a novel cyp26 gene (cyp26d1) in zebrafish that is expressed in hindbrain during early development. Using reverse-phase HPLC analyses, we show here that zebrafish Cyp26D1 expressed in 293T cells could metabolize all-trans RA, 9-cis RA, and 13-cis RA, but could not metabolize retinol or retinal. The metabolites of all-trans RA produced by Cyp26D1 were the same as that produced by Cyp26A1, which are mainly 4-hydroxy-all-trans-RA and 4-oxo-all-trans-RA. Performing mRNA microinjection into zebrafish embryos, we demonstrated that overexpression of Cyp26D1 in embryos not only caused the distance between rhombomere 5 and the first somite of the injected embryos to be shorter than control embryos but also resulted in left-right asymmetry of somitogenesis in the injected embryos. These alterations were similar to those caused by the overexpression of cyp26a1 in zebrafish embryos and to that which resulted from treating embryos with 1 microm 4-diethylamino-benzaldehyde (retinal dehydrogenase inhibitor), implying that cyp26d1 can antagonize RA activity in vivo. Together, our in vitro and in vivo results provided direct evidence that zebrafish Cyp26D1 is involved in RA metabolism.

Amino Acid Sequence↗
PubMed2006

Altered pericyte-endothelial relations in the rat retina during aging: implications for vessel stability.

Mural cells (smooth muscle cells and pericytes) regulate blood flow and contribute to vessel stability. We examined whether mural cell changes accompany age-related alterations in the microvasculature of the central nervous system. The retinas of young adult and aged Wistar rats were subjected to immunohistofluorescence analysis of alpha-smooth muscle actin (SMA), caldesmon, calponin, desmin, and NG2 to identify mural cells. The vasculature was visualized by lectin histochemistry or perfusion of horse-radish peroxidase, and vessel walls were examined by electron microscopy. The early stage of aging was characterized by changes in peripheral retinal capillaries, including vessel broadening, thickening of the basement membrane, an altered length and orientation of desmin filaments in pericytes, a more widespread SMA distribution and changes in a subset of pre-arteriolar sphincters. In the later stages of aging, loss of capillary patency, aneurysms, distorted vessels, and foci of angiogenesis were apparent, especially in the peripheral deep vascular plexus. The capillary changes are consistent with impaired vascular autoregulation and may result in reduced pericyte-endothelial cell contact, destabilizing the capillaries and rendering them susceptible to angiogenic stimuli and endothelial cell loss as well as impairing the exchange of metabolites required for optimal neuronal function. This metabolic uncoupling leads to reactivation of "physiological hypoxia" and angiogenesis in CNS aging.

Aging↗
PubMed2006

Encapsulation of drug reservoirs in fibers by emulsion electrospinning: morphology characterization and preliminary release assessment.

In this paper, we prepared composite fibers via electrospinning from either W/O or O/W emulsion. SEM images demonstrate the beads-in-string structures in these fibers and proved this technique to be an effective method for microencapsulation. As a practical application, Ca-alginate microspheres, which serve as reservoirs for hydrophilic drugs, were prepared in a reverse emulsion and then incorporated into poly (l-lactic acid) (PLLA) fibers by electrospinning. With the bovine serum albumin (BSA) loaded into the microspheres, the beads-in-string structure thus entrapped hydrophilic proteins in hydrophobic polymeric matrix. In the in vitro release test, BSA, which was released from composite fibers, achieved prolonged release profiles and lower burst release rates than those from naked Ca-alginate microspheres. In comparison with other well-established techniques to prepare microcapsules, such as solvent evaporation and spray-drying techniques, emulsion electrospinning features partly competing, partly complementary characteristics. Extension to other emulsion systems will be able to fabricate new types of functional structures.

Alginates↗
PubMed2006

Engineering of vascular grafts with genetically modified bone marrow mesenchymal stem cells on poly (propylene carbonate) graft.

Bone marrow mesenchymal stem cells (MSCs) have demonstrated their pluripotency to differentiate into different cell lineages and may be an alternative cell source for vascular tissue engineering. The objective of this study is to create small diameter vessels by seeding and culture of genetically modified MSCs onto a synthetic polymer scaffold produced by an electrospinning technique. A tubular scaffold (2 mm in diameter) with a microstructure of nonwoven fibers was produced by electrospinning of poly (propylene carbonate) (PPC). Rat MSCs obtained from bone marrow were expanded in culture and modified with vasculoprotective gene endothelial nitric oxide synthase (eNOS) or marker gene green fluorescent protein (GFP). These MSCs were seeded onto the electrospun fibrous grafts (internal diameter = 2 mm), and cultured in 5% CO(2) at 37 degrees C. The growth of MSCs in the scaffold was analyzed with scanning electron microscopy (SEM) and hematoxylin and eosin (H&E) staining. The gene transfer and transgenic gene expression were examined with fluorescence-activated cell sorting (FACS), immunochemical staining, reverse transcriptase-polymerase chain reaction (RT-PCR), and western blot. The production of nitric oxide (NO) by the engineered vessels was measured with an NO detection kit. Our data showed that the seeded cells integrated with the microfibers of the scaffold to form a three-dimensional cellular network, indicating a favorable interaction between this synthetic PPC scaffold with MSCs. High transduction efficiency was obtained with the use of concentrated retrovirus in the gene transfection of MSCs. The eNOS gene transcripts and protein were detected in the grafts seeded with eNOS-modified MSCs by RT-PCR and immunochemical staining. The amount of NO produced by grafts seeded with eNOS-modified MSCs was comparable to that produced by native blood vessels, and it was significantly higher than that in the grafts seeded with nonmodified MSCs. In summary, the vascular graft produced by culture of eNOS gene-modified MSCs onto the electrospun tubular scaffolds shows promising results in terms of function. The use of MSCs and therapeutic genes in tissue engineering of blood vessels could be helpful in improving vessel regeneration and patency.

Animals↗
PubMed2006

Complete genome sequence of Yersinia pestis strains Antiqua and Nepal516: evidence of gene reduction in an emerging pathogen.

Yersinia pestis, the causative agent of bubonic and pneumonic plagues, has undergone detailed study at the molecular level. To further investigate the genomic diversity among this group and to help characterize lineages of the plague organism that have no sequenced members, we present here the genomes of two isolates of the "classical" antiqua biovar, strains Antiqua and Nepal516. The genomes of Antiqua and Nepal516 are 4.7 Mb and 4.5 Mb and encode 4,138 and 3,956 open reading frames, respectively. Though both strains belong to one of the three classical biovars, they represent separate lineages defined by recent phylogenetic studies. We compare all five currently sequenced Y. pestis genomes and the corresponding features in Yersinia pseudotuberculosis. There are strain-specific rearrangements, insertions, deletions, single nucleotide polymorphisms, and a unique distribution of insertion sequences. We found 453 single nucleotide polymorphisms in protein-coding regions, which were used to assess the evolutionary relationships of these Y. pestis strains. Gene reduction analysis revealed that the gene deletion processes are under selective pressure, and many of the inactivations are probably related to the organism's interaction with its host environment. The results presented here clearly demonstrate the differences between the two biovar antiqua lineages and support the notion that grouping Y. pestis strains based strictly on the classical definition of biovars (predicated upon two biochemical assays) does not accurately reflect the phylogenetic relationships within this species. A comparison of four virulent Y. pestis strains with the human-avirulent strain 91001 provides further insight into the genetic basis of virulence to humans.

Bacterial Proteins↗
PubMed2006

Autocrine tumor necrosis factor alpha links endoplasmic reticulum stress to the membrane death receptor pathway through IRE1alpha-mediated NF-kappaB activation and down-regulation of TRAF2 expression.

NF-kappaB is critical for determining cellular sensitivity to apoptotic stimuli by regulating both mitochondrial and death receptor apoptotic pathways. The endoplasmic reticulum (ER) emerges as a new apoptotic signaling initiator. However, the mechanism by which ER stress activates NF-kappaB and its role in regulation of ER stress-induced cell death are largely unclear. Here, we report that, in response to ER stress, IKK forms a complex with IRE1alpha through the adapter protein TRAF2. ER stress-induced NF-kappaB activation is impaired in IRE1alpha knockdown cells and IRE1alpha(-/-) MEFs. We found, however, that inhibiting NF-kappaB significantly decreased ER stress-induced cell death in a caspase-8-dependent manner. Gene expression analysis revealed that ER stress-induced expression of tumor necrosis factor alpha (TNF-alpha) was IRE1alpha and NF-kappaB dependent. Blocking TNF receptor 1 signaling significantly inhibited ER stress-induced cell death. Further studies suggest that ER stress induces down-regulation of TRAF2 expression, which impairs TNF-alpha-induced activation of NF-kappaB and c-Jun N-terminal kinase and turns TNF-alpha from a weak to a powerful apoptosis inducer. Thus, ER stress induces two signals, namely TNF-alpha induction and TRAF2 down-regulation. They work in concert to amplify ER-initiated apoptotic signaling through the membrane death receptor.

Adenoviridae↗
PubMed2006

Ablation of PGC-1beta results in defective mitochondrial activity, thermogenesis, hepatic function, and cardiac performance.

The transcriptional coactivator peroxisome proliferator-activated receptor-gamma coactivator-1beta (PGC-1beta) has been implicated in important metabolic processes. A mouse lacking PGC-1beta (PGC1betaKO) was generated and phenotyped using physiological, molecular, and bioinformatic approaches. PGC1betaKO mice are generally viable and metabolically healthy. Using systems biology, we identified a general defect in the expression of genes involved in mitochondrial function and, specifically, the electron transport chain. This defect correlated with reduced mitochondrial volume fraction in soleus muscle and heart, but not brown adipose tissue (BAT). Under ambient temperature conditions, PGC-1beta ablation was partially compensated by up-regulation of PGC-1alpha in BAT and white adipose tissue (WAT) that lead to increased thermogenesis, reduced body weight, and reduced fat mass. Despite their decreased fat mass, PGC1betaKO mice had hypertrophic adipocytes in WAT. The thermogenic role of PGC-1beta was identified in thermoneutral and cold-adapted conditions by inadequate responses to norepinephrine injection. Furthermore, PGC1betaKO hearts showed a blunted chronotropic response to dobutamine stimulation, and isolated soleus muscle fibres from PGC1betaKO mice have impaired mitochondrial function. Lack of PGC-1beta also impaired hepatic lipid metabolism in response to acute high fat dietary loads, resulting in hepatic steatosis and reduced lipoprotein-associated triglyceride and cholesterol content. Altogether, our data suggest that PGC-1beta plays a general role in controlling basal mitochondrial function and also participates in tissue-specific adaptive responses during metabolic stress.

Adipose Tissue, Brown↗
PubMed2006

[Subcutaneous implantation of tissue-engineered heart valve leaflets in nude mice].

OBJECTIVE: To investigate the viability of tissue-engineered heart valve leaflets prepared with cell-polymer constructs in nude mice. METHODS: Sheep endothelial cells and smooth muscle cells/fibroblasts were seeded on patches of PHA and implanted subcutaneously in athymic mice (BALB/C). The cell-polymer constructs were harvested 12, 14, 21 and 28 days after implantation. RESULTS: Fourteen days after implantation, the cell-polymer constructs exhibited similar color with the autologous tissues, and HE staining showed more numerous cells in the implant. At 28 days following implantation, muscular fibers were formed in the cell-polymer constructs. V-G staining showed positive collagen staining in the implant at 12 days after implantation, while the control implants retrieved 28 days after implantation did not show extensive tissue formation or muscular fiber formation. CONCLUSION: The cell-polymer constructs can survive in vivo and has the potential to grow into autologous valve leaflets in the nude mice.

Animals↗
PubMed2006

[The study of salivary S-IgA antibody activity to clinical Streptococcus mutans in heat treated stress].

PURPOSE: The purpose of this study was to compare the salivary immunoglobulin A antibody response to Streptococcus mutans in normal with in heat treated stress. METHODS: Clinical Streptococcus mutans strains were isolated from 20 volunteers, serotyped by biochemical test and PCR, and genotyped by AP-PCR. Unstimulated secretions from submandibular glands and sublingual glands were collected from volunteers by modified collectors. Each identified genotype was cultured in two groups: control group was grown in BHI broth at 37 degrees C. for 3 hours; stress group was incubated in BHI broth at 42 degrees C. for 3 hours. Analysis of SIgA activity to clinical genotype strains and reference strains in different group was detected by Western blot. RESULTS: There was no significant difference between stress group and control group,in spite that some bands had strong or weak intensity. Different genotypes of S.mutans could have different immunoblotting profile as for an individual. SIgA from different volunteers could have different immonoblotting profiles as to the same genotype strain. CONCLUSIONS: Although Streptococcus mutans can express heat shock proteins in stress, this study suggests these new proteins have no significant effect on the reaction of SIgA to Streptococcus mutans. Different genotype strains may have different proteins, and different immunoreactivity to host. Different hosts may have different immunoreactivities to one genotypes of S.mutans.

Blotting, Western↗
PubMed2006

[Kinetics and mechanism in bleomycin-induced murine pulmonary fibrosis model].

OBJECTIVE: To investigate the kinetics of pathogenesis of bleomycin induced pulmonary fibrosis and its mechanism in mice. METHODS: Thirty six male ICR mice were randomized as a negative control (NC) group and pulmonary fibrosis model (FM) groups (FMA, FMB, FMC, FMD, FME sub groups). Except for NC group, mice in the other groups were given bleomycin by nasal instillation. Animals in each group were sacrificed on day 6, 14, 21, 28 and 35, respectively. T lymphocytes were quantified for Th1/Th2 and Tc1/Tc2 by flow cytometry. Accumulation of inflammatory cells in bronchioalveolar lavage fluid (BALF) was quantified by cell count. The sections of the right lung were stained with either hematoxylin eosin (HE) or Masson trichrome. The left lung was weighed and its hydroxyproline (HYP) content was assayed. Multi cytokine expression in lung tissue was assayed by semi quantitative reverse transcription polymerase chain reaction (RT-PCR). On day 35, the tidal volume (V(T)), forced expiratory volume in 1 second/forced vital capacity (FEV 0.1/FVC), static compliance (Cst) of mice were determined before they were sacrificed. RESULTS: (1)The total cell number in BALF in pulmonary fibrosis groups was statistically significantly higher than that in NC group (all P<0.01), and HYP content in lung tissue in pulmonary fibrosis groups was statistically significantly increased than that in NC group except for group FMA (all P<0.01). (2)V(T) and Cst in FME group were statistically significantly decreased than those in NC group (both P<0.01), and FEV 0.1/FVC was statistically significantly increased (P<0.05). (3)Th1 and Tc1 were demonstrated as the dominant expression in the acute inflammatory stage; Th2 and Tc2 were the dominant expression in the fibrosis forming stage, and then Th1 and Tc1 were again the dominant expression at the terminal stage of pulmonary fibrosis. (4)Compared with the content of cytokine in the lung in NC group, the expression of transforming growth factor-beta1 (TGF-beta1) and tissue inhibitor of metalloproteinase-1 (TIMP-1) mRNA were significantly higher in FM groups (all P<0.01). CONCLUSION: The changes in lung function of bleomycin-induced pulmonary fibrosis in mice are typical of that of restrictive ventilatory disorder. Th2, Tc2 and fibrotic promoting growth factors (TGF-beta1, TIMP-1, etc.) play pivotal roles in the pathogenesis of pulmonary fibrotic process.

Animals↗