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Biomedical subjects

P Jiang

Publications and source records attributed to P Jiang.

At least 55 records · Page 3Linked to original sources
PubMed1999

Integrin-associated protein is a ligand for the P84 neural adhesion molecule.

P84 (also known as SHPS-1, BIT, and SIRP) is a heterophilic adhesive membrane protein involved in receptor tyrosine kinase signaling that is found at synapses in the mammalian central nervous system and in non-neural tissues. We have identified a binding partner for P84 using an expression cloning strategy. Here we report that integrin-associated protein (IAP/CD47) is a predominant binding partner of P84. Immunohistochemistry reveals a virtually identical distribution of P84 and IAP in a variety of adult brain regions. Because IAP has been implicated in cell signaling in cells of the immune system, P84 and IAP represent a heterophilic binding pair that is likely to be involved in bi-directional signaling at the synapse and in other tissues.

Amino Acid Sequence↗
PubMed1999

Foot landing position during gait influences ground reaction forces.

OBJECTIVE: The purpose of this study was to determine how foot landing position influenced the ground reaction forces of two coordinate systems during gait. DESIGN: Values of ground reaction forces components as expressed in two coordinate systems (room, foot) were used to compare ground reaction forces of different foot landing position. BACKGROUND: Non-neutral foot landing position during gait could influence the mechanics of the whole body motion and/or the foot-ankle complex and produce different ground reaction forces patterns compared to a neutral foot landing position. METHODS: Thirty females were assigned to a foot landing group: toe-out, toe-in or neutral. Each participant walked 10 trials across a force platform while three-dimensional motion was captured. RESULTS: No differences were observed for vertical or anteroposterior ground reaction forces variables between groups for either coordinate system. For medio-lateral forces of both coordinate systems, toe-out participants exhibited greater first lateral and second medial maximum forces and exhibited greater impulses. CONCLUSION: For toe-out participants, greater medio-lateral ground reaction forces of the room coordinate system indicate excessive forces are generated by toe-out participants that do not contribute to moving the participant forward. Furthermore, medio-lateral loading on the foot increases proportionally with the degree of toe-out. RELEVANCE: Establishing norms for clinical populations requires understanding of factors that can influence ground reaction force (GRF). Foot landing position (FLP) only affects the medio-lateral forces. Excessive toe-out landing has been surmised to be related to injury. Greater forces acting medio-laterally to the foot's long axis may have a relevant effect on in/eversion loading of the foot.

Ankle Joint↗
PubMed1999

Recurrent varicose veins: patterns of reflux and clinical severity.

Duplex scanning was used to determine patterns of recurrent varicose veins in 264 limbs and to relate these to clinical factors. All limbs had previously undergone sapheno-femoral ligation in the groin. A recurrent sapheno-femoral junction was present in 172 (65.2%). Incompetence was found in long or short saphenous veins in 232 limbs (87.9%), perforators in 176 (66.7%), and deep veins in 156 (59.1%). Residual long saphenous veins were present in 43.4% and 73.6% of limbs that were with and without stripped long saphenous veins, respectively. An incompetent thigh perforator was present in 14.0% and 15.3% of these two groups, respectively. Multiple sites of incompetence were observed in the majority (75.4%). In general, no particular reflux pattern in the groin was related to an increased incidence of ulceration. However, ulceration was more frequent in limbs with deep reflux to knee or below-knee levels. None of those with isolated reflux in the groin that was unrelated to the common femoral vein had ulceration. The pattern of reflux was unrelated to striping or non-striping of the long saphenous veins and the time since initial surgery. A history of deep vein thrombosis was invariably associated with some degree of deep reflux. A system of recurrent patterns in the groin is described for the purpose of surgical audit. In 15.1%, recurrence was attributed with some confidence to inadequate surgery. These results indicate that the pattern of recurrence is highly variable and often with multiple sites of incompetence. In a few instances, the pattern of recurrence was associated with specific clinical factors. A full work-up including duplex scanning is recommended.

Aged↗
PubMed1999

Development of a high metastatic orthotopic model of human renal cell carcinoma in nude mice: benefits of fragment implantation compared to cell-suspension injection.

In this study we compared the metastatic rate of human renal cell carcinoma SN12C in two orthotopic nude mouse models: surgical orthotopic implantation (SOI) of histologically intact tumor tissue and cellular orthotopic injection (COI) of cell suspensions in the kidney. The primary tumors resulting from SOI were larger and much more locally invasive than primary tumors resulting from COI. SOI generated higher metastatic expression than COI. The differences in metastatic rates in the involved organs (lung, liver, and mediastinal lymph nodes) were 2-3 fold higher in SOI compared to COI (P < 0.05). Median survival time in the SOI model was 40 days, which was significantly shorter than that of COI (68 days) (P < 0.001). Histological observation of the primary tumors from the SOI model demonstrated a much richer vascular network than the COI model. Lymph node and lung metastases were larger and more cellular in the SOI model compared to COI. We conclude that the tissue architecture of the implanted tumor tissue in the SOI model plays an important role in the initiation of primary tumor growth, invasion, and distant metastasis. This study directly demonstrates that the implantation of histologically intact tumor tissue orthotopically allows accurate expression of the clinical features of human renal cancer in nude mice. This model should be of value in cancer research and antimetastatic drug discovery for renal cancer, a currently very poorly responding malignancy.

Adult↗
PubMed1999

An ultra-metastatic model of human colon cancer in nude mice.

An ultra-high metastatic model of human colon cancer was developed in order to represent highly malignant patient disease for which there is no current model. Surgical orthotopic implantation (SOI) of a histologically intact liver metastasis fragment derived from a surgical specimen of a patient with metastatic colon cancer was initially implanted in the colon, liver and subcutaneously in nude mice. This tumor did not metastasize for the first 10 passages. At the eleventh passage, the tumor exhibited metastasis from the colon to the liver, spleen, and lymph nodes. At this time, two selective passages were carried out by transplanting resulting liver metastases in the nude mice to the colon of additional nude mice. After these two passages, the tumor became stably ultra-metastatic and was termed AC3488UM. One-hundred percent of mice transplanted with AC3488UM with SOI to the colon exhibited local growth, regional invasion, and spontaneous metastasis to the liver, lymph nodes, and spleen. While the maximum size of the primary tumor was 0.9 g, the metastatic liver was over 9 times the weight of the normal liver with the maximum weight of the metastatic liver over 12 g. Liver metastases were detected by the tenth day after transplantation in all animals. Half the animals died of metastatic tumor 25 days after transplantation. Histological characteristics of AC3488UM tumor were poorly differentiated adenocarcinoma of colon. Mutant p53 is expressed heterogeneously in the primary tumor and more homogeneously in the liver metastasis suggesting a possible role of p53 in the liver metastasis. The human origin of AC3488UM was confirmed by positive fluorescence staining for in situ hybridization of human DNA. The AC3488 human colon-tumor model with its ultra-high metastatic capability in each transplanted animal, short latency and a short median survival period is different from any known human colon cancer model and will be an important tool for the study of and development of new therapy for highly metastatic human colon cancer.

Animals↗
PubMed1999

Regulation of autophosphorylation of Escherichia coli nitrogen regulator II by the PII signal transduction protein.

The nitrogen regulator II (NRII or NtrB)-NRI (NtrC) two-component signal transduction system regulates the transcription of nitrogen-regulated genes in Escherichia coli. The NRII protein has both kinase and phosphatase activities and catalyzes the phosphorylation and dephosphorylation of NRI, which activates transcription when phosphorylated. The phosphatase activity of NRII is activated by the PII signal transduction protein. We showed that PII was also an inhibitor of the kinase activity of NRII. The data were consistent with the hypothesis that the kinase and phosphatase activities of two-component system kinase/phosphatase proteins are coordinately and reciprocally regulated. The ability of PII to regulate NRII is allosterically controlled by the small-molecule effector 2-ketoglutarate, which binds to PII. We studied the effect of 2-ketoglutarate on the regulation of the kinase and phosphatase activities of NRII by PII, using a coupled enzyme system to measure the rate of cleavage of ATP by NRII. The data were consistent with the following hypothesis: when not complexed with 2-ketoglutarate, PII cannot bind to NRII and has no effect on its competing NRI kinase and phosphatase activities. Under these conditions, the kinase activity of NRII is dominant. At low 2-ketoglutarate concentrations, PII trimers complexed with a single molecule of 2-ketoglutarate interact with NRII to inhibit its kinase activity and activate its phosphatase activity. However, at high 2-ketoglutarate concentrations, PII binds additional ligand molecules and is rendered incapable of binding to NRII, thereby releasing inhibition of NRII's kinase activity and effectively inhibiting its phosphatase activity (by failing to stimulate it).

Adenosine Triphosphate↗
PubMed1999

Expression of intestinal trefoil factor in developing rat intestine.

Intestinal trefoil factor (ITF or TFF3), a small peptide secreted at the mucosal surface by goblet cells throughout the mature intestine, appears to play important roles in the maintenance and repair of the intestinal mucosal barrier. To study the expression of TFF3 during development, intestinal tissues were collected from rats at different development stages and examined by Northern blot analysis, Western blot analysis and immunohistochemical staining for TFF3 mRNA and protein expression. The results demonstrate that rat TFF3 mRNA is not detected until the 17th gestational day (term = 22 days), the expression is greater on gestational day 20 and increased further postnatally. TFF3 protein is first detected by Western blotting and immunohistochemical staining on gestational day 20. Further increases in TFF3 protein expression are demonstrated at around the weaning period. In conclusion, significant expression of rat TFF3 commences late in gestation and its expression is relatively deficient in immature rats. Expression of TFF3 may be deficient in premature infants and, therefore, may have a role in the development of necrotizing enterocolitis.

Animals↗
PubMed1999

Application of the polymerase chain reaction to detect fowl adenoviruses.

The possibility of using the polymerase chain reaction (PCR) for the detection of fowl adenoviruses (FAdV) was tested. The optimal reaction parameters were evaluated and defined for purified genomic DNA of type 8 fowl adenovirus (FAdV-8), and then the same conditions were applied for nucleic acid extracted from infected cells. One hundred picograms of purified viral DNA, or 250 FAdV-8-infected cells, were detected by ethidium bromide staining of the PCR products in agarose gels. The sensitivity was increased to 10 pg purified viral DNA, or 25 infected cells, when the PCR products were hybridized with a specific labeled probe. Several field isolates of FAdV and the CELO virus (FAdV serotype 1) could be amplified by the same primers and conditions, but the size of the amplicons was smaller than that for the FAdV-8 PCR product. Other avian viruses and uninfected cell cultures tested negative.

Adenoviridae Infections↗
PubMed1999

Genetically fluorescent melanoma bone and organ metastasis models.

We report here the establishment and metastatic properties of bright, highly stable, green fluorescent protein (GFP) expression transductants of the B16 mouse malignant melanoma cell line and the LOX human melanoma line. The highly fluorescent malignant melanoma cell lines allowed the visualization of skeletal and multiorgan metastases after i.v. injection of B16 cells in C57BL/6 mice and intradermal injection of LOX cells in nude mice. The melanoma cell lines were transduced with the pLEIN expression retroviral vector containing the GFP and neomycin resistance genes. Stable B16F0 and LOX clones expressing high levels of GFP were selected stepwise in vitro in levels of G418 of up to 800 microg/ml. Extensive bone and bone marrow metastases of B16F0 were visualized by GFP expression when the animals were sacrificed 3 weeks after cell implantation. Metastases for both cell lines were visualized in many organs, including the brain, lung, pleural membrane, liver, kidney, adrenal gland, lymph nodes, skeleton, muscle, and skin by GFP fluorescence. This is the first observation of experimental skeletal metastases of melanoma, which was made possible by GFP expression. These models should facilitate future studies of the mechanism and therapy of bone and multiorgan metastasis of melanoma.

Animals↗
PubMed1999

[Detection of S-gene mutation strain in vertical transmission of HBV and its significance].

OBJECTIVE: To study S-gene mutation of hepatitis B virus (HBV) in its vertical transmission and its significance. METHODS: Nucleotides of S-gene NT451-660 of HBV were sequenced with dideoxy end termination technique in four female and six male carriers without HBV markers in their spouses and in their intrauterine infected fetuses. RESULTS: It was showed that homology of HBV nucleotide and amino acid sequences in the mothers, fathers and their fetuses was very high. Mutation at the sites 491, 494, 530, 546 and 581 of S-gene resulted in amino acid substitution at the sites 113, 114, 126, 131 and 143, respectively. Mutations at the sites 126 were detected in two pairs of mother or father and her or his fetuses and mutations at the sites 131 in four fetuses, respectively, including combined mutation at the site 143 in two fetuses. CONCLUSION: Strains with S-gene mutation, mainly at the sites 126, 131 and 143, could be found in HBV vertical transmissions, which could cause failure in HB vaccine immunization.

Adult↗
PubMed1999

[HBV transmission from father to foetus and HBV DNA in tissues outside the liver].

OBJECTIVE: To study the possibility of HBV Transmission from father to foetus and HBV DNA in tissues outside liver. METHODS: Paired sera were from 8 HBV man carriers whose wives were negative for HBVM and 8 foetuses who were infected with HBV in the womb. S gene nt 451-660 nucleotide, C gene nt 2,022-2,321 nucleotide were directly sequenced. RESULTS: The homology of HBV sequence between father and foetus was very high. The mutations of 491, 494, 530, 546 and 581 nucleotide in the S gene caused 113, 114, 126, 131 and 143 amino acid substitution. HBV DNA can be detected in the tissues outside liver of foetus. CONCLUSION: HBV transmission from father to foetus may be present. HBV DNA in tissues outside liver of foetus can be detected.

Adult↗
PubMed1999

[Effects of A, D-genome chromosomes on photosynthetic carbonassimilation in common wheat] [In Process Citation]

Photosynthetic traits of ditelosomic lines with A, D-genome in CS (Chinese Spring) were investigated in this paper. The both arms of 4A-chromosome have the positive effects on photosynthetic rate, active photosynthetic duration(APD), chlorophyll content and mesophyll conductance. The short arms of 1A and both arms of 6D also have positive effects on photosynthetic rate and APD. But the long arms of 4D have negative effects on photosynthetic rate, APD and RuBPCase activity. The short arms of 2A, long arms of 5A, 6D and 7D negatively affect on RuBPCase content. So, 4A, 4D and some other chromosomes have shown important effects on photosynthesis in common wheat.

Journal Article↗
PubMed1999

[Experimental study on anti-cancer effect of Cantharidine derivatives and platinum complex].

OBJECTIVE: To certify the anti-tumor effects of the four Cantharidine derivatives and platinum complex on transplanted tumor in mice to search for new anti-tumor drugs. METHODS: Complex of four Cantharidine derivatives (Dpt 1-15, Dpt 5-10, Dpt 12-3 and Dpt6-2) and platinum were given to tumor beating mice of transplanted S180 sarcoma, H22 solid hepatocarcinoma and ascites hepatocarcinoma through intraperitoneal or intravenous injection, and the effect of treatment on tumor weight and survival of animal were observed. Cisplatin was used as positive control and 0.9% normal saline used as negative control. All data were treated with t test. RESULTS: All the four complex had anti-tumor effect. The inhibition rate of Dpt5-10 and Dpt1-15 on S180 sarcoma and H22 solid hepatocarcinoma and the survival prolongation rate of Dpt5-10 on H22 ascites hepatocarcinoma were similar to those of cisplatin. The toxicity of effective dose of Dpt1-15 was rather high. CONCLUSIONS: Cantharidine derivatives and platinum complex is new effective anti-tumor drug, among them the Dpt5-10 is the most effective one. Further study for improving the solubility of drug is necessary and study the difference of cross resistance between the new complex and cisplatinum.

Animals↗
PubMed1999

[In vitro hepatic targeting tendency of galactosyl-anti CD3 McAb-TILS].

This study was undertaken to enhance the hepatic targeting tendency of tumor infiltrating lymphocytes (TILs) and hence to lower the recurrence rate of primary liver cancer after hepatectomy. Galactosyl-anti CD3McAb-TILs were prepared and then were incubated together with hepatocytes. Their interaction through asialoglycoprotein receptor-mediated mechanism was observed under the inverted phase contrast microscope. The carbohydrate density of galactosyl-anti CD3McAb and the combining rate of galactosyl-anti CD3McAb with TILs were measured. The results revealed that galactosyl-anti CD3 McAb-TIL obviously were adhered to hepatocytes. The carbohydrate density of galactosyl-anti CD3McAb was 62.18, and the combining rate of galactosyl-anti CD3McAb with TILs was 97.9%. The results suggested that in vitro hepatic targeting tendency of galactosyl-anti CD3McAb-TILs was satisfactory, and that the carbohydrate density of 62.18 and the combining rate of 97.9% ensured the effective use of TILs.

Animals↗
PubMed1999

[Expression of genes aroG and pheA in phenylalanine biosynthesis].

aroG and pheA genes, encoding 3-Deoxy-D-arabinoheptulonate-7-phosphate synthase(DS) and Chorismate mutase (CM)-prephenate dehydratase(PD) in the pathway of phenylalanine biosynthesis respectively, were amplified by polymerase chain reaction(PCR). The genes were assembled on the multicopy vectors and expressed in both Escherichia coli and Brevibacterium. The products of two gene were detected by SDS-PAGE. The activities of relevant enzymes were measured in the crude extract of the host strain. When aroG-pheA genes were introduced into E. coli p2392, the activities of DS, CM and PD were increased by 4.3-fold, 4.4-fold and 2.2-fold respectively. Whereas in the case of Brevibacterium flavum 2732, the activities of DS, CM and PD were increased by 12.3-fold, 2.3-fold and 5.6-fold, respectively. As the results, the overproduction of phenylalanine was brought about by using the genetic engineering strain of B. flavum.

3-Deoxy-7-Phosphoheptulonate Synthase↗
PubMed1998

Widespread skeletal metastatic potential of human lung cancer revealed by green fluorescent protein expression.

To understand the skeletal metastatic pattern of non-small cell lung cancer, we developed a stable high-expression green fluorescent protein (GFP) transductant of human lung cancer cell line H460 (H460-GFP). The GFP-expressing lung cancer was visualized to metastasize widely throughout the skeleton when implanted orthotopically in nude mice. H460 was transduced with the pLEIN retroviral expression vector containing the enhanced GFP and the neomycin (G418) resistance gene. A stable high GFP-expressing clone was selected in vitro using 800 microg/ml G418. Stable high-level expression of GFP was maintained in s.c.-growing tumors formed after injecting H460-GFP cells in nude mice. To use H460-GFP for visualization of metastasis, fragments of s.c.-growing H460-GFP tumors were implanted by surgical orthotopic implantation in the left lung of nude mice. Subsequent micrometastases were visualized by GFP fluorescence in the contralateral lung, plural membrane, and widely throughout the skeletal system including the skull, vertebra, femur, tibia, pelvis, and bone marrow of the femur and tibia. The use of GFP-expressing H460 cells transplanted by surgical orthotopic implantation revealed the extensive metastatic potential of lung cancer in particular to widely disseminated sites throughout the skeleton. This new metastatic model can play a critical role in the study of the mechanism of skeletal and other metastasis in lung cancer and in screening of therapeutics that prevent or reverse this process.

3T3 Cells↗
PubMed1998

Reconstitution of the signal-transduction bicyclic cascade responsible for the regulation of Ntr gene transcription in Escherichia coli.

Nitrogen-regulation of gene transcription in Escherichia coli results from the regulation of the phosphorylation state of the enhancer-binding transcription factor NRI (NtrC). We examined the regulation of NRI phosphorylation in a reconstituted bicyclic cascade system containing four regulatory proteins: NRI, the signal-transducing uridylyltransferase/uridylyl-removing enzyme (UTase/UR), its substrate the signal transduction protein PII, and the kinase/phosphatase NRII (NtrB), which is a PII receptor that phosphorylates and dephosphorylates NRI. In this reconstituted system, the phosphorylation state of NRI was regulated reciprocally by the small molecule effectors glutamine, which prevented the accumulation of NRI-P, and 2-ketoglutarate, which caused accumulation of NRI-P. Regulation of the bicyclic system by glutamine was exclusively due to sensation and signal-transduction by the UTase/UR-PII monocycle, which was observed to function essentially as a glutamine-sensing apparatus. In contrast, regulation of NRI phosphorylation by 2-ketoglutarate, which binds to PII, was due to direct regulation of the NRII-PII interaction and the rate of NRI-P dephosphorylation. Thus, the PII protein transduces the glutamine signal to the NRII-NRI monocycle in the form of its uridylylation state and is also the receptor of the antagonistic 2-ketoglutarate signal, which blocks the activity of unmodified PII.

Bacterial Proteins↗