Biomedical subjects

Jianping Zhou

Publications and source records attributed to Jianping Zhou.

14 recordsLinked to original sources

PubMed2025

CRISPR-Cas9-mediated knockout of OsKCS11 in rice reveals potential crosstalk between very-long-chain fatty acids and cytokinin.

Very-long-chain fatty acids (VLCFAs) play crucial roles in various physiological processes in plants. Through our investigation using a CRISPR-Cas9 knockout mutant library in rice, we identified a semi-dwarf rice mutant named CRISPR-Cas-based dwarf-1 (csd-1). This mutant displayed multiple developmental defects, such as decreased plant height, panicle length, seed size, and seed-setting rate. Whole-genome resequencing analysis revealed that a T-nucleotide insertion in β-ketoacyl-CoA synthase 11 (KCS11), responsible for the initial step in fatty acid elongation, was responsible for the observed defects in csd-1. The identity of csd-1 was confirmed through genetic complementation and CRISPR-Cas9-mediated knockout. Expression analysis indicated that OsKCS11 was present in various tissues, with differential abundance observed through RT-qPCR and promoter GUS staining, and strong localization at the node position by RNA in situ hybridization; furthermore, OsKCS11 protein was confirmed to be in the endoplasmic reticulum. Furthermore, csd-1 exhibited significantly reduced levels of linolenic acid (18:3), C24:0-OH, C28:0-alkanes, C29:0-alkanes, alpha-tocopherol, and C33:0-alkanes, while trans-nonadecenoic acid and behenic acid levels were increased. Cytokinin analysis revealed significant increases in isopentenyladenine (IPA) and cis-zeatin (cZ) levels in csd-1. Molecular investigations indicated upregulation of genes involved in cytokinin biosynthesis or signaling, suggesting a potential link between VLCFAs and cytokinin synthesis through acetyl-CoA. This study not only proposed an alternative gene mapping method based on whole-genome resequencing but also elucidated the mechanism by which VLCFAs influence cytokinin synthesis and signaling.

Oryza↗

PubMed2007

Expression of Gadd45a and p53 proteins in human pancreatic cancer: potential effects on clinical outcomes.

BACKGROUND AND OBJECTIVES: p53 gene has a dual role as a trigger of apoptosis and as an initiator of DNA repair. Gadd45a gene assumes the function to maintain the stability of genome. The present study was designed to assess the significance of Gadd45a and p53 protein expression on pancreatic cancer. METHODS: The expression of p53 and Gadd45a was immunohistochemically studied in 59 patients with pancreatic cancer. RESULTS: The positive expression rate of p53 and Gadd45a was 67.8% and 42.4%, respectively. p53 expression in the patients <65 years was significantly higher than that in the patients >or=65 years (P=0.030). Gadd 45a expression showed no correlation to the patients' age. There was no relation for p53 expression to differentiation and TNM stages. Gadd 45a expression showed significant difference in histological differentiation (P=0.007). The median survival time of p53(+) and Gadd45a(+) group was shorter than that of p53(-) and Gadd45a(-) group (P>0.05), respectively. Meanwhile, the median survival time of p53 (+)Gadd45a(+) group was also shorter than that of p53(-)Gadd45a(-) group (P>0.05). CONCLUSIONS: p53 and Gadd45a proteins are both highly expressed in pancreatic cancer. The overexpression of p53 and Gadd45a may have connection with the malignant biologic behavior of pancreatic cancer.

Adult↗

PubMed2007

Phosphorylated acidic serine-aspartate-rich MEPE-associated motif peptide from matrix extracellular phosphoglycoprotein inhibits phosphate regulating gene with homologies to endopeptidases on the X-chromosome enzyme activity.

Inactivating PHEX (phosphate regulating gene with homologies to endopeptidases on the X chromosome) mutations cause X-linked hypophosphatemia in humans and mice (Hyp) through overproduction of fibroblast growth factor 23 (FGF23) a phosphaturic factor, by osteocytes. Matrix extracellular phosphoglycoprotein (MEPE) is also elevated in Hyp and other hypophosphatemic disorders. In addition, the administration of an ASARM (acidic serine-aspartate rich MEPE-associated motif) peptide derived from MEPE causes phosphaturia and inhibits bone mineralization in mice, suggesting that MEPE also plays a role in phosphate homeostasis. Since recent studies found that MEPE binds specifically to PHEX in vitro, we tested the effect of recombinant-MEPE and its ASARM peptide on PHEX enzyme activity in vitro and FGF23 expression in bone marrow stromal cell cultures ex vivo. We found that both recombinant MEPE and synthetic phosphorylated ASARM peptide (ASARM-PO(4)) inhibit PHEX enzyme activities in an in vitro fluorescent-quenched PHEX enzyme activity assay. The ASARM-PO(4) peptide inhibits PHEX enzyme activity in a dose-dependent manner with a K(i) of 128 nM and V(max-i) of 100%. Recombinant MEPE also inhibits PHEX activity (K(i) = 2 nM and V(max-i) = 26%). Long-term bone marrow stromal cell cultures supplemented with 10 microM ASARM-PO(4) peptide resulted in significant elevation of FGF23 transcripts and inhibition of mineralization. These findings suggest that MEPE inhibits mineralization and PHEX activity and leads to increased FGF23 production. The resulting coordination of mineralization and release of a phosphaturic factor by MEPE may serve a physiological role in regulating systemic phosphate homeostasis to meet the needs for bone mineralization.

Animals↗

PubMed2006

Fibroblast growth factor 23 is a counter-regulatory phosphaturic hormone for vitamin D.

The regulation of the phosphaturic factor fibroblast growth factor 23 (FGF23) is not well understood. It was found that administration of 1,25-dihydroxyvitamin D(3) (1,25[OH](2)D(3)) to mice rapidly increased serum FGF23 concentrations from a basal level of 90.6 +/- 8.1 to 213.8 +/- 14.6 pg/ml at 8 h (mean +/- SEM; P < 0.01) and resulted in a four-fold increase in FGF23 transcripts in bone, the predominate site of FGF23 expression. In the Hyp-mouse homologue of X-linked hypophosphatemic rickets, administration of 1,25(OH)(2)D(3) further increased circulating FGF23 levels. In Gcm2 null mice, low 1,25(OH)(2)D(3) levels were associated with a three-fold reduction in FGF23 levels that were increased by administration of 1,25(OH)(2)D(3). In osteoblast cell cultures, 1,25(OH)(2)D(3) but not calcium, phosphate, or parathyroid hormone stimulated FGF23 mRNA levels and resulted in a dose-dependent increase in FGF23 promoter activity. Overexpression of a dominant negative vitamin D receptor inhibited 1,25(OH)(2)D(3) stimulation of FGF23 promoter activity, and mutagenesis of the FGF23 promoter identified a vitamin D-responsive element (-1180 GGAACTcagTAACCT -1156) that is responsible for the vitamin D effects. These data suggest that 1,25(OH)(2)D(3) is an important regulator of FGF23 production by osteoblasts in bone. The physiologic role of FGF23 may be to act as a counterregulatory phosphaturic hormone to maintain phosphate homeostasis in response to vitamin D.

Animals↗

PubMed2006

Pathogenic role of Fgf23 in Hyp mice.

Inactivating mutations of the PHEX (phosphate-regulating gene with homologies to endopeptidases on the X chromosome) endopeptidase, the disease-causing gene in X-linked hypophosphatemia (XLH), results in increased circulating levels of fibroblastic growth factor-23 (FGF23), a bone-derived phosphaturic factor. To determine the causal role of FGF23 in XLH, we generated a combined Fgf23-deficient enhanced green fluorescent protein (eGFP) reporter and Phex-deficient Hyp mouse model (Fgf23(+/-)/Hyp). eGFP expression was expressed in osteocytes embedded in bone that exhibited marked upregulation of eGFP in response to Phex deficiency and in CD31-positive cells in bone marrow venules that expressed low eGFP levels independently of Phex. In bone marrow stromal cells (BMSCs) derived from Fgf23(-/-)/Hyp mice, eGFP expression was also selectively increased in osteocyte-like cells within mineralization nodules and detected in low levels in CD31-positive cells. Surprisingly, eGFP expression was not increased in cell surface osteoblasts, indicating that Phex deficiency is necessary but not sufficient for increased Fgf23 expression in the osteoblast lineage. Additional factors, associated with either osteocyte differentiation and/or extracellular matrix, are necessary for Phex deficiency to stimulate Fgf23 gene transcription in bone. Regardless, the deletion of Fgf23 from Hyp mice reversed the hypophosphatemia, abnormal 1,25(OH)(2)D(3) levels, rickets, and osteomalacia associated with Phex deficiency. These results suggest that Fgf23 acts downstream of Phex to cause both the renal and bone phenotypes in Hyp mice.

Animals↗

PubMed2006

Liquid chromatography/tandem triple-quadrupole mass spectrometry for determination of paclitaxel in rat tissues.

A liquid chromatography/tandem triple-quadrupole mass spectrometry assay to quantify paclitaxel in rat tissue homogenates containing taxol or paclitaxel nanoliposome (PTX-NLP) was developed and validated. Liquid-liquid extraction with tert-butyl methyl ether was used for tissue sample preparation and docetaxel was used as the internal standard. Paclitaxel and docetaxel were separated on a 200 mm x 4.6 mm x 5 microm C(18) column and quantified using a triple-quadrupole mass spectrometer operating in positive ion electrospray selective reaction monitoring mode (ESI(+)-SRM) with a total run time of 6.0 min. The peak area of the m/z 876.3 --> 307.9 transition of paclitaxel is measured versus that of the m/z 830.3 --> 549.1 transition of docetaxel to generate the standard curves. The standard curves were linear over the concentration range of 0.2008-2008 ng/mL for different tissues. The method had high extraction recovery (>90%) and accuracy (>90%) with the intra-day and inter-day precision <15%. Frozen stability, freeze/thaw stability, extraction stability and solution stability at ambient temperature were examined, which indicated the tissue samples should be extracted within 5 days and avoid being frozen and thawed repeatedly over 5 times. Extracted samples after evaporation could be stored at -20 degrees C for 20 days without drug degradation and no degradation was also observed after solution samples were left to stand at ambient temperature for 24 h. This assay was used to support an in vivo biodistribution study of PTX-NLP in rats.

Animals↗

PubMed2006

Special paraunitary matrices, Cayley transform, and multidimensional orthogonal filter banks.

We characterize and design multidimensional (MD) orthogonal filter banks using special paraunitary matrices and the Cayley transform. Orthogonal filter banks are represented by paraunitary matrices in the polyphase domain. We define special paraunitary matrices as paraunitary matrices with unit determinant. We show that every paraunitary matrix can be characterized by a special paraunitary matrix and a phase factor. Therefore, the design of paraunitary matrices (and thus of orthogonal filter banks) becomes the design of special paraunitary matrices, which requires a smaller set of nonlinear equations. Moreover, we provide a complete characterization of special paraunitary matrices in the Cayley domain, which converts nonlinear constraints into linear constraints. Our method greatly simplifies the design of MD orthogonal filter banks and leads to complete characterizations of such filter banks.

Algorithms↗

PubMed2006

Multidimensional multichannel FIR deconvolution using Gröbner bases.

We present a new method for general multidimensional multichannel deconvolution with finite impulse response (FIR) convolution and deconvolution filters using Gröbner bases. Previous work formulates the problem of multichannel FIR deconvolution as the construction of a left inverse of the convolution matrix, which is solved by numerical linear algebra. However, this approach requires the prior information of the support of deconvolution filters. Using algebraic geometry and Gröbner bases, we find necessary and sufficient conditions for the existence of exact deconvolution FIR filters and propose simple algorithms to find these deconvolution filters. The main contribution of our work is to extend the previous Gröbner basis results on multidimensional multichannel deconvolution for polynomial or causal filters to general FIR filters. The proposed algorithms obtain a set of FIR deconvolution filters with a small number of nonzero coefficients (a desirable feature in the impulsive noise environment) and do not require the prior information of the support. Moreover, we provide a complete characterization of all exact deconvolution FIR filters, from which good FIR deconvolution filters under the additive white noise environment are found. Simulation results show that our approaches achieve good results under different noise settings.

Algorithms↗

PubMed2006

The nonsubsampled contourlet transform: theory, design, and applications.

In this paper, we develop the nonsubsampled contourlet transform (NSCT) and study its applications. The construction proposed in this paper is based on a nonsubsampled pyramid structure and nonsubsampled directional filter banks. The result is a flexible multiscale, multidirection, and shift-invariant image decomposition that can be efficiently implemented via the à trous algorithm. At the core of the proposed scheme is the nonseparable two-channel nonsubsampled filter bank (NSFB). We exploit the less stringent design condition of the NSFB to design filters that lead to a NSCT with better frequency selectivity and regularity when compared to the contourlet transform. We propose a design framework based on the mapping approach, that allows for a fast implementation based on a lifting or ladder structure, and only uses one-dimensional filtering in some cases. In addition, our design ensures that the corresponding frame elements are regular, symmetric, and the frame is close to a tight one. We assess the performance of the NSCT in image denoising and enhancement applications. In both applications the NSCT compares favorably to other existing methods in the literature.

Algorithms↗

PubMed2005

Role of matrix extracellular phosphoglycoprotein in the pathogenesis of X-linked hypophosphatemia.

X-linked hypophosphatemia (XLH), a disorder characterized by hypophosphatemia, impaired skeletal mineralization, and aberrant regulation of 1, 25(OH)(2)D(3), is caused by inactivating mutations of Phex, which results in the accumulation of putative phosphaturic factors, called phosphatonins. Matrix extracellular phosphoglycoprotein (Mepe) is a proposed candidate for phosphatonin. The authors found that Hyp mice had increased expression of the MEPE and another phosphaturic factor, Fgf23. To establish MEPE's role in the pathogenesis of the XLH, Mepe-deficient mice were back-crossed onto the Hyp mouse homologue of XLH and phenotypes of wild-type, Mepe(-/-), Hyp, and Mepe(-/-)/Hyp mice were examined. Transfer of Mepe deficiency onto the Phex-deficient Hyp mouse background failed to correct hypophosphatemia and aberrant serum 1,25(OH)(2)D(3) levels. Increased Fgf23 levels in Hyp mice were not affected by superimposed Mepe deficiency. In addition, Mepe-deficient Hyp mice retained bone mineralization defects in vivo, characterized by decreased bone mineral density, reduced mineralized trabecular bone volume, lower flexural strength, and histologic evidence of osteomalacia; however, cultures of Hyp-derived bone marrow stromal cells in the absence of Mepe showed improved mineralization and normalization of osteoblast gene expression profiles observed in cells derived from Mepe-null mice. These results demonstrate that MEPE elevation in Hyp mice does not contribute to the hypophosphatemia associated with inactivating Phex mutations and is therefore not phosphatonin.

Animals↗

PubMed2005

Multidimensional orthogonal filter bank characterization and design using the Cayley transform.

We present a complete characterization and design of orthogonal infinite impulse response (IIR) and finite impulse response (FIR) filter banks in any dimension using the Cayley transform (CT). Traditional design methods for one-dimensional orthogonal filter banks cannot be extended to higher dimensions directly due to the lack of a multidimensional (MD) spectral factorization theorem. In the polyphase domain, orthogonal filter banks are equivalent to paraunitary matrices and lead to solving a set of nonlinear equations. The CT establishes a one-to-one mapping between paraunitary matrices and para-skew-Hermitian matrices. In contrast to the paraunitary condition, the para-skew-Hermitian condition amounts to linear constraints on the matrix entries which are much easier to solve. Based on this characterization, we propose efficient methods to design MD orthogonal filter banks and present new design results for both IIR and FIR cases.

Algorithms↗

PubMed2003

The influence of insulin on secretion of IGF-I and IGFBP-I in cultures of human endometrial stromal cells.

OBJECTIVES: To study the influence of insulin on IGF-I and IGFBP-I secretion of the human endometrial stromal cells. METHODS: Late proliferative phase endometrial stromal cells were isolated from endometrium tissues and then cultured for 24 h in Hams F-12 only as a control and in Hams F-12 with different concentrations of estradiol (E2) and insulin (INS) as treated groups. Simultaneously, the endometrial stromal cells from late secretory phase endometrium were cultured for 24 h in Hams F-12 only as a control and in Hams F-12 supplemented with different concentrations of progesterone (P) and insulin as treated groups. After 24 h of culturing, the mediums were collected for either IGF-I or IGFBP-I assays. RESULT: The concentrations of IGF-I in medium from cultured endometrial stromal cells in the proliferative phase were 0.78 +/- 0.47 ng/ml in the hormone-free control group; 1.44 +/- 0.59 ng/ml and 1.39 +/- 0.33 ng/ml in 100 pg/ml E2 group and 20 microU/ml INS group, which was higher than that of the control group (P < 0.05 and P < 0.01, respectively). The IGF-I concentration in the 100 microU/ml INS group was 2.03 +/- 0.53 ng/ml, which was higher than that of the 20 micro U/ml INS group (P < 0.01). Levels of IGF-I in the 100 pg/ml E2 plus 20 microU/ml INS group was 2.18 +/- 0.36 ng/ml, which was significantly higher than that of the 20 microU/ml INS and 100 pg/ml E2 group (P < 0.01), but lower than that of the 100 pg/ml E2 plus 100 microU/ml INS group (3.42 +/- 0.75 ng/ml), P < 0.01. The concentration of IGFBP-I in medium from cultured endometrial stromal cells in the secretory phase was 2.50 +/- 1.39 ng/ml in the hormone-free control group and 5.44 +/- 2.09 ng/ml in the 10 pg/ml P group, which was significantly higher than that of the control (P < 0.01). IGFBP-I concentration in 20 microU/ml INS group was 0.16 +/- 0.58 ng/ml, which was lower compared with control, but higher compared with the 100 microU/ml INS group (P < 0.01). The level of IGFBP-I in the 10 ng/ml P plus 20 microU/ml INS group was 2.10 +/- 1.17 ng/ml, lower compared with the 10 ng/ml P group, but higher compared with the 10 pg/ml P plus 100 microU/ml INS group, P < 0.01. CONCLUSIONS: Insulin can stimulate basal (without hormone) and E2-stimulated IGF-I secretion in cultured stromal cells from human late proliferative endometrium in a dose-dependent manner. Insulin can suppress basal (without hormone) and P-stimulated IGFBP-I secretions in cultured stromal cells from human secretory endometrium in a dose-dependent manner.

Cells, Cultured↗

PubMed2002

New designed HMBA agents as inducers of erythroleukemia cell differentiation.

OBJECTIVE: Searching for more potent and less toxic HMBA-related agents. METHODS: Human erythroleukemia cell K562, murine erythroleukemia cell (MEL) and its sub-line MEL DS19 were used as target cells to select a cell line which is the most sensitive to HMBA, then analyzed the activity of inducing differentiation of two new designed HMBA derivatives: HMBPA [hexamethylenebi (3-pyridin) amide] and Co-HDTA (ethylenediaminetetra acetic acid cobalt) using cell biology, cytochemical and molecular biology techniques. RESULTS: We found that the MEL DS19 cells were most sensitive to HMBA (benzidine positive, B+ approximately 76%). Co-HDTA can inhibit the growth of MEL DS19, but induces differentiation just in a small population (B+ 2% approximately 4.5%). Between 0.02 approximately 5 micromol/L, HMBPA induces 3% approximately 8% cells committed to differentiation with little inhibition of cell proliferation. 1 micromol/L HMBPA and 2 mmol/L HMBA together, can obviously increase the percentage of differentiated cell (B+ approximately 72%), inhibit DNA synthesis and accelerate beta-globin transcription. CONCLUSION: The new HMBA derivatives may provide potential cancer differentiation inducers.

Acetamides↗

PubMedDate not supplied

Determination of paclitaxel in rat plasma by LC-MS-MS.

A simple, rapid, and sensitive liquid chromatography-mass spectrometry (MS)-MS method for quantitating paclitaxel in rat plasma is developed. Liquid-liquid extraction with tert-butyl methyl ether is used for sample preparation, and docetaxel is used as the internal standard. Paclitaxel and docetaxel are separated on a C18 column and quantitated using a triple-quadrupole MS operating in positive ion electrospray selective reaction monitoring mode with a total run time of 6.0 min. The peak area of the m/z 876.3 --> 307.9 transition of paclitaxel is measured versus that of the m/z 830.3 --> 549.1 transition of docetaxel to generate the standard curve. The standard curve is linear over the concentration range of 0.2008-1004 ng/mL for rat plasma. The method has high extraction recovery (> 90%) and accuracy (> 90%), with the intra- and interday precision < 15%. Frozen stability, freeze-and-thaw stability, extracted stability, and room temperature solution stability are also examined. This assay is used to support a pharmacokinetic study of paclitaxel self-assembled nanoliposome in rats.

Animals↗