Biomedical subjects

Zhao Wang

Publications and source records attributed to Zhao Wang.

At least 55 records · Page 3Linked to original sources

PubMed2004

Cloning of a full-length cDNA of human testis-specific spermatogenic cell apoptosis inhibitor TSARG2 as a candidate oncogene.

A novel human gene full-length cDNA sequence-TSARG2 was identified from a human testis cDNA library using the SRG2 gene (GenBank Accession No. ), which was significantly up-regulated in cryptorchidism, as an electronic probe. TSARG2 was 1223 bp in length. The putative protein encoded by this gene was 305 amino acids with a theoretical molecular weight of 34,751 and isoelectric point of 9.85. The sequence shared no significant homology with any known protein in databases except SRG2. Northern blot analysis revealed that 1.7 kb TSARG2 transcript was detected selectively in human testis. Furthermore, results of in situ hybridization assay confirmed that TSARG2 was expressed in seminiferous tubules, more precisely in spermatogonia and spermatocyte. No mutation was found by PCR-SSCP in 122 cases of azoospermia, severe oligzoospermia, and cryptorchidism. The green fluorescence produced by pEGFP-C1/TSARG2 was detected on the nucleus of COS7 cells after 24h post-transfection. The pcDNA3.1(-)/TSARG2 plasmid was constructed and introduced into MCF7 cells by liposome transfection. TSARG2 can accelerate MCF7 cells to traverse the S-phase and enter the G2-phase compared with the control without transfection of TSARG2, which suggested that this gene plays an important role in the development of cryptorchid testis and is a testis-specific apoptosis candidate oncogene.

Amino Acid Sequence↗

PubMed2004

Inhibitory effect of tellimagrandin I on chemically induced differentiation of human leukemia K562 cells.

Tellimagrandin I is a hydrolysable tannin compound widely present in plants. In this study, the effect of tellimagrandin I on chemically induced erythroid and megakaryocytic differentiation was investigated using K562 cells as differentiation model. It was found that tellimagrandin I not only inhibited the hemoglobin synthesis in butyric acid (BA)- and hemin-induced K562 cells with IC50 of 3 and 40microM, respectively, but also inhibited other erythroid differentiation marker including acetylcholinesterase (AChE) and glycophorin A (GPA) in BA-induced K562 cells. Tellimagrandin I also inhibited 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced expression of CD61 protein, a megakaryocytic marker. RT-PCR analysis showed that tellimagrandin I decreased the expression of erythroid genes (gamma-globin and porphobilinogen deaminase (PBGD)) and related transcription factors (GATA-1 and NF-E2) in BA-induced K562 cells, whereas tellimagrandin I induced the overexpresison of GATA-2 transcription factor that played negative regulation on erythroid differentiation. These results indicated that tellimagrandin I had inhibitory effects on erythroid and megakaryocytic differentiation, which suggested that tannins like tellimagrandin I might influence the anti-tumor efficiency of some drugs and the hematopoiesis processes.

Acetylcholinesterase↗

PubMed2004

Mitochondrial dysfunction as an early event in the process of apoptosis induced by woodfordin I in human leukemia K562 cells.

Tannins are a group of widely distributed plant polyphenols, some of which are beneficial to health because of their chemopreventive activities. In the present study, we investigated the effects and action mechanisms of woodfordin I, a macrocyclic ellagitannin dimer, on human chronic myelogenous leukemia (CML) K562 cells. The results showed that woodfordin I was able to suppress the proliferation and induce apoptosis in K562 cells. Apoptosis was evaluated by cytomorphology, internucleosomal DNA fragmentation, and externalization of phosphatidylserine. Woodfordin I treatment caused a rapid and sustained loss of mitochondrial transmembrane potential (MMP), transient generation of reactive oxygen species (ROS), transient elevation of intracellular Ca2+ concentration, and cytosolic accumulation of cytochrome c. The activation of caspase-9 and 3, but not caspase-8, was also demonstrated, indicating that the apoptotic signaling triggered by woodfordin I was mediated through the intrinsic mitochondria-dependent pathway. Western blot and immunofluorescence analysis revealed that the anti-apoptotic Bcl-2 and Bcl-xL levels were downregulated, together with the pro-apoptotic Bax protein. Significantly, woodfordin I-induced apoptosis was associated with a decline in the levels of c-Abl, Bcr-Abl, and cellular protein tyrosine phosphorylation. Considering the consequence of all the events in the process of woodfordin I-induced apoptosis, the mitochondrial dysfunction is directly responsible for the pro-apoptotic effects on K562 cells. Furthermore, because CML is a malignancy of pleuripotent hematopoietic cells caused by the dysregulated tyrosine kinase activity of Bcr-Abl, these findings suggest that woodfordin I may be a potential lead compound against CML.

Apoptosis↗

PubMed2004

Medroxyprogesterone acetate, but not progesterone, protects against inflammation-induced parturition and intrauterine fetal demise.

OBJECTIVE: This study was undertaken to determine whether progestational agents can prevent inflammation-induced preterm parturition and fetal demise. STUDY DESIGN: The activation of contractile and inflammatory pathways in response to localized intrauterine inflammation was investigated by using quantitative polymerase chain reaction (PCR). Serum progesterone (P4) levels and alterations in progesterone receptor-B (PR-B) were determined with radioimmunoassay and quantitative PCR, respectively. With our in vivo model of intrauterine inflammation, animals were randomly assigned to pretreatment with P4 or medroxyprogesterone acetate (MPA) before intrauterine lipopolysaccharide (LPS). Animals were observed for preterm delivery. The number of live pups 48 hours after intrauterine LPS was recorded for each treatment group. The ability of MPA to alter signal transduction pathways leading to preterm parturition were investigated by quantitative PCR and histochemical studies. RESULTS: Intrauterine inflammation is associated with decreased serum progesterone levels and decreased transcription of PR-B. Preterm delivery rates were 100% for LPS alone, 63% for LPS+P4, and 0% for LPS+MPA. No live pups remained at 48 hours in the LPS or LPS+P4 groups. Pretreatment with MPA significantly preserved fetal viability. MPA suppressed activation of contraction-associated genes and inflammatory mediators and prevented cervical ripening in response to intrauterine inflammation. CONCLUSION: MPA, with its progestational and anti-inflammatory properties, prevented inflammation-induced preterm parturition and significantly preserved fetal viability.

Animals↗

PubMed2004

An absence of CCR5 on donor cells results in acceleration of acute graft-vs-host disease.

OBJECTIVE: Chemokines have been postulated to play a role in the pathogenesis of graft-vs-host disease (GVHD) after allogeneic hematopoietic transplantation. Recent reports have indicated that the absence of donor expression of CCR5 on T cells ameliorates GVHD in models using no conditioning of the recipient. We therefore assessed the role of CCR5 on donor cells in models where intensive conditioning of the recipient occurs, thus more appropriately mirroring the clinical experience. METHODS: Lethally irradiated mice received allogeneic bone marrow transplants. Recipients were given full MHC-mismatched donor bone marrow and splenocytes from CCR5 knockout (KO) mice vs wild-type (WT) control donors. RESULTS: Recipients of CCR5 KO donor cells succumbed to acute GVHD at an accelerated rate compared to mice receiving WT cells. Donor CD8+ T cells expanded to a significantly greater extent in recipients of CCR5 KO vs WT control cells. T cells recovered from recipients of CCR5 KO cells produced more IFN-gamma and TNF-alpha and proliferated to a T-cell mitogen at a significantly greater level then T cells from recipients of WT cells, indicating that CCR5 plays a role in downregulating donor alloreactive CD8+ T-cell expansion. Histological assessment of the mice indicated pathological lesions in the kidneys and a greater degree of liver pathological changes in mice that received CCR5 KO donor grafts. CONCLUSIONS: These results indicate that the role of CCR5 in allogeneic bone marrow transplants and GVHD is more complex than initially thought. In a murine transplant model with intensive conditioning, the overall effect of absent CCR5 expression on donor cells results in greater GVHD and donor T-cell expansion.

Acute Disease↗

PubMed2004

Effect of leonurine on the activity of creatine kinase.

The effects of leonurine (1) on the activity of creatine kinase (CK) have been studied. The results show that leonurine inhibits enzyme activity in concentration- and time-dependent manners (at 0.75 and 1.51 mmol from 12 to 72 h). There are two mechanisms for the inhibition process. Compound 1 first acts as a non-competitive inhibitor and then as an irreversible inhibitor. Changes of CK were not found in 10% SDS-PAGE, but the amount of dimeric CK decreased in 10% non-SDS gel. The results suggest that 1 can inhibit CK activity by degrading its dimeric structure.

Creatine Kinase↗

PubMed2004

The mitotic-arresting and apoptosis-inducing effects of diosgenyl saponins on human leukemia cell lines.

Diosgenyl saponins are the most abundant steroid saponins, and exert a large variety of biological functions. In a previous report, we showed that dioscin was able to induce cytotoxicity and apoptosis in human myeloblast leukemia HL-60 cells. This study further investigated the action mechanisms underlying this effect. The activation of caspase-9 and -3, but not caspase-8, together with the down-regulation of anti-apoptotic Bcl-2 protein, demonstrated that the apoptotic signaling triggered by dioscin was mediated through the intrinsic mitochondria-dependent pathway. We also investigated its anti-proliferative effect on human chronic myelogenous leukemia K562 cells. Flow cytometry analysis showed that dioscin treatment induced the accumulation of cells in the G(2)/M phase. Cytomorphology with DAPI and Wright-Giemsa staining demonstrated the enlargement of cell volume and multinucleation in the treated cells. Subsequent apoptosis was delineated with phosphatidylserine externalization and DNA hypodiploidy. Trillin was one of the hydrolysates of dioscin. We demonstrated that it could induce multinucleation in HL-60, K562 and human promyelocytic leukemia NB(4) cells, suggesting its extensive mitotic-arresting effects. As the diosgenyl sapogenin, diosgenin was also shown to be able to induce multinucleation and apoptosis in K562 cells in a similar manner to dioscin. These findings suggest that diosgenyl saponins have the properties to induce mitotic arrest and apoptosis, suggesting that they may be a new kind of antimitotic agent.

Antineoplastic Agents, Phytogenic↗

PubMed2004

Dual effects of cycloheximide on U937 apoptosis induced by its combination with VP-16.

In this study, cycloheximide (CHX) and VP-16 alone and in combination (C&V) have been used to strongly trigger apoptosis in U937 cells. The presence of CHX markedly prevented VP-16-induced apoptosis, suggesting that in this process de novo protein synthesis is required. But interestingly, C&V had shown more similarities with CHX but not VP-16 alone, including the effects on cell cycle distribution and induction of apoptosis, which occurred more quickly and was steadily enhanced by increasing concentrations of CHX or by N-alpha-tosyl-L-lysyl-chloromethyl ketone (TLCK), a serine protease inhibitor. These results indicate that CHX, not VP-16, is indeed the dominant inducer of U937 apoptosis, when they are coadministered. In particular, VP-16 even promoted CHX-induced apoptosis, but did not alter its selection of cell types. In T-cells resistant to CHX (Molt-4), we have detected no apoptotic response to their combination. These findings may well explain why the inhibitory effects of CHX on apoptosis induced by the same stimuli are usually different according to the cell type used, and also suggest that CHX may have the potential to lower side effects and drug resistance of cancer therapy.

Antineoplastic Agents, Phytogenic↗

PubMed2004

Cloning and characterization of testis-specific spermatogenesis associated gene homologous to human SPATA4 in rat.

Rat SPATA4 gene, homologue to the human and mouse SPATA4 gene, expressed specifically in the rat testis was cloned by informatics analysis. The cDNA mapped to chromosome 16 in the rat genome is made up of 6 exons and the exon-intron boundaries obey to the AG/GT rule. The gene contains a 972 bp open reading frame encoding 323 amino acid sequences with theoretical molecular weight of 36.64 KD and isoelectric point of 9.65. One CpG island is located in the gene from site -200 to +198. A typical promoter is also predicted from site -630 to +101. According to the computer-aided analysis of the putative protein encoded by the rat SPATA4, no transmembrane region and no signal peptides are found in the protein. Multi-tissue RT-PCR results show that the SPATA4 gene is expressed specifically in the testis only. Moreover, the expression of SPATA4 occurs in a development stage-dependent pattern. According to the RT-PCR results, no expression of SPATA4 is detected until the rat is 30 d old after birth. The amount of SPATA4 mRNA increases from 30-d to 65-d-old rat and then keeps stable after that. In conclusion, this study proves the conservation of SPATA4 in mammalian animals and predicts its important role in spermatogenesis.

Amino Acid Sequence↗

PubMed2004

Cytoplasm prepared from all-trans retinoic acid (ATRA)-treated human hematopoietic progenitor cells induces differentiation of both ATRA sensitive and ATRA resistant leukemia cells.

In this study, hematopoietic cells from human placental blood were treated with the differentiation-inducing drug all-trans retinoic acid (ATRA). Their cytoplasm was then used to culture the human myelogenous leukemia cell line HL60, NB(4) cells and the RA-resistant HL60-R and NB(4)-R(2) cells. All of these four kinds of leukemia cells underwent macrophage/monocyte differentiation and apoptosis, while their proliferation was inhibited. This suggests that the RA receptors were not essentially needed in this situation, and this method should be applicable in the treatment of RA-resistant promyelocytic leukemia as well as other kinds of leukemia.

Apoptosis↗

PubMed2004

Effects of chebulinic acid on differentiation of human leukemia K562 cells.

AIM: To study effects of chebulinic acid on erythroid and megakaryocytic differentiation in K562 cells. METHODS: The benzidine staining method was used to evaluate hemoglobin synthesis; the expression of erythroid specific glycophorin A (GPA) protein and megakaryocytic surface marker CD61 was determined by flow cytometry using fluorescence labeled antibodies; erythroid and megakaryocytic mRNA expression was analyzed by RT-PCR. RESULTS: During erythroid differentiation induced by butyric acid (BA) or hemin, chebulinic acid not only inhibited the hemoglobin synthesis of BA- and hemin-treated K562 cells in concentration-dependent manner with IC50 of 4 micromol/L and 40 micromol/L respectively, but also inhibited another erythroid differentiation marker acetylcholinesterase at the concentration of 50 micromol/L in the cells either treated or untreated with each erythroid differentiation inducers, whereas chebulinic acid 50 micromol/L did not change GPA protein expression in these cells significantly. When K562 cells were treated with TPA 50 microg/L for 72 h to induce megakaryocytic differentiation, the presence of chebulinic acid 50 micromol/L slightly provoked the decrease of GPA protein expression induced by TPA. Chebulinic acid did not change the TPA-induced CD61 expression at the same concentration. Chebulinic acid also reduced the mRNA levels of erythroid relative genes including gamma-globin, PBGD, NF-E2, and GATA-1 genes in K562 cells either treated or untreated with BA, whereas chebulinic acid upregulated the mRNA levels of GATA-2 transcription factor in these cells. CONCLUSION: Chebulinic acid had inhibitory effect on erythroid differentiation likely through changing transcriptional activation of differentiation relative genes, which suggests that chebulinic acid or other tannins might influence the efficiency of some anti-tumor drugs-induced differentiation or the hematopoiesis processes.

Acetylcholinesterase↗

PubMed2004

[Pharmacological study of Limax extract on inhibiting H14 cell].

OBJECTIVE: To study the inhibitive effect of Limax extract on H14 and inducement effect of apoptosis and differentiation of H14 cells in vitro. METHODS: MTT method, DNA gel electrophoresis, cell stain and microscope observation. RESULTS: After H14 cell line was induced by Limax extract, the growth of H14 cell was inhibited in vitro and the morpha of the cells changed. CONCLUSION: Limax extract had inhibitive effect on H14 cell, partially by apoptosis, and partially by differentiation.

Animals↗

PubMed2004

Down-regulation of mitotic checkpoint in transformed human embryo lung fibroblasts induced by N-methyl-N'-nitro-N-nitrosoguaridine.

BACKGROUND: Mutations in mitotic checkpoint genes have been detected in several human cancers, which exhibit chromosome instability. We wanted to know whether mutation of hBub1 could occur in transformed human embryo lung fibroblasts (HELF) cells induced by a chemical carcinogen. METHODS: HELF cells were transformed by N-methyl-N'-nitro-N-nitrosoguaridine (MNNG), and three flasks of transformed HELF cells (named as T1, T2, and T3) were selected as amplifiers, and mutations of hBub1 in these transformed cells were analyzed by PCR-SSCP and sequencing. RESULTS: It was found that any one of three transformed cell lines exhibited aneuploidy with a low mitotic checkpoint function. Subsequent PCR-SSCP and sequence analysis showed an AGT to CGT or ATT mutation at codon 80 in hBub1 gene in T1 cells with a resultant change in amino acid sequence. CONCLUSION: Our study demonstrated that the mitotic checkpoint genes could be targets of MNNG.

Cell Line, Transformed↗

PubMed2004

[Mesorectal spread and circumferential margin involvement of rectal cancer studied on large slice].

OBJECTIVE: To provide the mode of cancer distribution in the mesorectum and circumferential resection margin. METHODS: Large slice technique was used in the pathologic study of 62 specimens operated on following the principles of total mesorectal excision (TME). RESULTS: More than 40% of all the observed neoplastic foci were located in the outer layer of the mesorectum in Stage III patients. Further analysis of the foci's localities with respect to the primary tumor's locality showed that ipsolateral neoplastic foci (44.44%) were significantly more than the contralateral neoplastic foci (13.33%) in the mesorectum (P<0.05). Extramural distal spread was found in 8 cases with the maximum extent of 3.5 cm. No significant difference in occurrence of circumferential margin involvement (CMI) was observed among tumors of different location, but tumors of poorer differentiation were noted to have a higher risk of CMI. CONCLUSION: Large slice technique offers a whole image of rectum, mesorectum, together with the position of neoplastic foci. There are outer preponderance and lateral discrepancy of neoplastic foci distribution in the mesorectum. A distal clearance margin of 4 cm would be mandatory. We advocate the adoption of TME as the baisc surgical principles in treating patients with rectal cancer and in avoiding surgery-related circumferential margin involvement.

Adenocarcinoma↗

PubMed2004

[On PACAP-aggravated experimental acute pancreatitis].

The role of PACAP (pituitary adenylate cyclase activating polypeptide), a peptidergic transmitter, in the pathogenesis of acute pancreatitis is not yet clear. This experiment was conducted to examine the action of exogenous PACAP on rat pancreas and on the course of experimental acute pancreatitis. The results showed that 5-30 microg/kg of PACAP slightly raised the serum amylase level, induced pancreatic edema (23.88% +/- 2.532%-25.86% +/- 1.974% of experiment groups versus 29.21% +/- 5.657% of control group), inflammatory cell infiltration, vacuolization of acinar cells, and occasionally fatty and parenchymal necroses. 15-30 microg/kg of PACAP aggravated cerulein-induced acute pancreatitis; the pancreatic edema became more marked (13.45% +/- 2.045%-17.66% +/- 4.652% of expreiment groups versus 21.83% +/- 3.013% of cerulein group, P<0.05), the serum amylase level became higher; and ascites, pancreatic bleeding, fatty and parenchymal necroses, and extensive vacuolization of acinar cells appeared. For sodium taurocholate-induced pancreatitis, 5-10 microg/kg of PACAP mildly attenuated the pancreatic edema, reduced the serum amylase level (1986.91 +/- 710.97-2944.33 +/- 1182.47 IU/L vs 3690.87 +/- 2277.99 IU/L, P<0.05), whereas it caused multifocal hemorrhage and prominent necrosis in pancreas. Except the cerulein-induced pancreatitis groups, other groups were found to have reduced pancreatic functional capillary density (FCD); when pancreatic edema was taken into consideration and calibrated FCD was introduced (FCD weighted against pancreatic wet/dry ratio), all groups revealed increases in pancreatic functional capillaries when compared with normal control. In conclusion, PACAP is proinflammatory in the pathogenesis of acute pancreatitis, PACAP plus cerulein can induce acute hemorrhagic/necrotizing pancreatitis, and the action of PACAP on cerulein-induced panceatitis may differ from that on sodium taurocholate-induced one. In this experiment, pancreatic FCD was underestimated due to pancreatic edema.

Amylases↗

PubMed2003

Molecular cloning and expression of a pearl oyster (Pinctada fucata) homologue of mammalian putative tumor suppressor QM.

The QM gene was originally identified as a putative tumor suppressor gene from a Wilms' tumor cell line by subtractive hybridization assay. Later studies showed that the QM protein is multifunctional, involved in cell growth and differentiation, energy metabolism, respiration, and cytoskeletal function. In this report a full-length complementary DNA encoding a QM counterpart in pearl oyster (Pinctada fucata) was isolated. Phylogenetic analysis shows that oyster QM is more closely related to its insect homologues than to the mammalian homologues. Analysis of the tissue expression pattern of the oyster QM gene showed that oyster QM messenger RNA is expressed in all tissues tested, with highest levels in the digestive gland and mantle. Furthermore, we expressed the QM protein in Escherichia coli; Western blotting showed that the antibody of human QM is immunoreactive to the expressed oyster QM protein. Incubation of the oyster QM with Zn2+ resulted in the reduction of intrinsic emission fluorescence and a red-shift in the lambda(max) emission, indicating the occurrence of Zn(2+)-induced conformational changes. This evidence presents a possible mechanism for the critical function of zinc ion in the interaction of QM with Jun.

Amino Acid Sequence↗

PubMed2003

A new model for inflammation-induced preterm birth: the role of platelet-activating factor and Toll-like receptor-4.

Preterm birth is a leading cause of neonatal morbidity and mortality. Despite a growing body of evidence correlating inflammation with preterm birth, the signal transduction pathways responsible for the emptying of the uterus in the setting of intrauterine inflammation has not been elucidated. We now report a unique, reproducible mouse model of localized intrauterine inflammation. This model results in 100% preterm delivery with no maternal mortality. Using our model, we also show that platelet-activating factor is a crucial mediator of both inflammation-induced preterm birth and fetal demise. Using C3H/HeJ mice, we demonstrate that toll-like receptor-4 (TLR-4) plays a role in lipopolysaccharide-induced preterm birth but not in inflammation-induced fetal death. Immunohistochemistry studies demonstrate the presence of the platelet-activating factor receptor in both endometrial glands and smooth muscle in uterine tissues. Molecular studies demonstrate the differential expression of platelet-activating factor receptor and TLR-4 in uterine and cervical tissue throughout gestation. Quantitative polymerase chain reaction revealed an up-regulation of TLR-4 in the fundal region of the uterus in response to intrauterine inflammation. The use of this model will increase our understanding of the significant clinical problem of inflammation-induced preterm birth and will elucidate signal transduction pathways involved in an inflammatory state.

Animals↗

PubMed2003

Laparoscopic total mesorectal excision of low rectal cancer with preservation of anal sphincter: a report of 82 cases.

AIM: To assess the feasibility and efficacy of laparoscopic total mesorectal excision (LTME) of low rectal cancer with preservation of anal sphincter. METHODS: From June 2001 to June 2003, 82 patients with low rectal cancer underwent laparoscopic total mesorectal excision with preservation of anal sphincter. The lowest edge of tumors was below peritoneal reflection and 1.5-7 cm from the dentate line (1.5-5 cm in 48 cases, 5-7 cm in 34 cases). RESULTS: LTME with anal sphincter preservation was performed on 82 randomized patients with low rectal cancer, and 100 % sphincter preservation rate was achieved. There were 30 patients with laparoscopic low anterior resection (LLAR) at the level of the anastomosis below peritoneal reflection and 2 cm above from the dentate line; 27 patients with laparoscopic ultralow anterior resection (LULAR) at the level of anastomoses 2 cm below from the dentate line; and 25 patients with laparoscopic coloanal anastomoses (LCAA) at the level of the anastomoses at or below the dentate line. No defunctioning ileostomy was created in any case. The mean operating time was 120 minutes (ranged from 110-220 min), and the mean operative blood loss was 20 mL (ranged from 5-120 mL). Bowel function was restored and diet was resumed on day 1 or 2 after operation. The mean hospital stay was 8 days (ranged from 5-14). Postoperative analgesics were used in 45 patients. After surgery, 2 patients had urinary retention, one had anastomotic leakage, and another 2 patients had local recurrence one year later. No interoperative complication was observed. CONCLUSION: LTME with preservation of anal sphincter is a feasible, safe and minimally invasive technique with less postoperative pain and rapid recovery, and importantly, it has preserved the function of the sphincter.

Adult↗