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Biomedical subjects

Q Dong

Publications and source records attributed to Q Dong.

At least 55 records · Page 3Linked to original sources
PubMed2000

[Study of apoptosis in the male rat spermatogenic cells after vasostomy].

OBJECTIVE: To investigate the effect of vasostomy on apoptosis in the male rat spermatogenic cells after vasoligation. METHODS: Model of vasoligation and vasostomy in male rat was established, and then terminal deoxynucleotidyl transferase-mediated dUTP nick labelling technique to detect the apoptosis of spermatogenic cells at 4, 8, 12, 16 weeks after vasostomy. RESULTS: The number of apoptotic cells in vasostomy group was significantly lower than that of vasoligation group since 8 weeks after vasostomy(P < 0.05). The number of apoptotic cells in 8 and 12 weeks after vasostomy were significantly higher than that in prevasoligation(P < 0.05). 16 weeks after vasostomy, the number of apoptotic cells restored to the level same as that in prevasoligation stage. CONCLUSION: Vasostomy can reverse the apoptosis of spermatogenic cells due to vasoligation.

Animals↗
PubMed2000

[Effect of vasostomy on expression of Bcl-2 and Bax gene in rat spermatogenic cells].

The objective of this study was to explore the change of Bcl-2 and Bax gene expression in rat spermatogneic cells after vasostomy. A rat model with vasoligation and vasostomy was set up and then used for detecting the protein expression of Bcl-2 and Bax gene at 4, 8, 12, 16 weeks after vasostomy by means of immunohistochemistry. Sixty rats were randomly distributed into three groups named vasoligation group (VG), vasostomy group(VOG) and sham-operation group(SOG) respectively. The results showed that the Bcl-2 protein expression in VOG group increased gradually and came to be significantly higher than that in VG group 8 weeks after vasostomy, and it's level was the same as that in SOG group at the 12th week. The bax protein expressions in VG and VOG groups were significantly higher than that in SOG group, but there was no difference between VOG and VG groups. In conclusion, the change of Bcl-2 protein expression observed in this study is indicative of the anti-apoptosis function of Bcl-2 gene in both the status of being vasoligated and vasostomized, whereas the consistent Bax protein expression before and often the repatency of the vas suggests further researches into its effect on apoptosis of spermatogenic cells.

Animals↗
PubMed1999

Dynamic DNA hybridization on a chip using paramagnetic beads.

Dynamic DNA hybridization is presented as an approach to perform gene expression analysis. The method is advantageous because of its dynamic supplies of both DNA samples and probes. The approach was demonstrated on a microfluidic platform by incorporating paramagnetic beads as a transportable solid support. A glass chip was fabricated to allow simultaneous interrogation of eight DNA target samples by DNA probes. DNA targets were immobilized on beads via streptavidin-biotin conjugation or base pairing between oligonucleotide residues. The DNA/bead complex was introduced into the device in which hybridization took place with a complementary probe. The hybridized probe was then removed by heat denaturation to allow the DNA sample to be interrogated again by another probe with a different sequence of interest. A pneumatic pumping apparatus was constructed to transport DNA probes and other reagents into the microfluidic device while hydrostatic pumping was used for the introduction of paramagnetic beads with samples. After investigating three types of paramagnetic beads, we found Dynabeads Oligo(dT)25 best suited this application. Targets on the beads could be sequentially interrogated by probes for 12 times, and the hybridization signal was maintained within experimental variation. Demonstration of specific hybridization reactions in an array format was achieved using four synthesized DNA targets in duplicate and five probes in sequence, indicating the potential application of this approach to gene expression analysis.

Actins↗
PubMed1999

Negative regulation of myeloid cell proliferation and function by the SH2 domain-containing tyrosine phosphatase-1.

The SH2 domain containing tyrosine phosphatase SHP-1 has been implicated in the regulation of a multiplicity of signaling pathways involved in hemopoietic cell growth, differentiation, and activation. A pivotal contribution of SHP-1 in the modulation of myeloid cell signaling cascades has been revealed by the demonstration that SHP-1 gene mutation is responsible for the overexpansion and inappropriate activation of myelomonocytic populations in motheaten mice. To investigate the role of SHP-1 in regulation of myeloid leukocytes, an HA epitope-tagged dominant negative (interfering) SHP-1 (SHP-1C453S) was expressed in the myelo-monocytic cell line U937 using the pcDNA3 vector. Overexpression of this protein in SHP-1C453S transfectants was demonstrated by Western blot analysis and by detection of decreased specific activity. Growth, proliferation, and IL-3-induced proliferative responses were substantially increased in the SHP-1C453S-overexpressing cells relative to those in control cells. The results of cell cycle analysis also revealed that the proportion of cells overexpressing SHP-1C453S in S phase was greater than that of control cells. The SHP-1C453S-expressing cells also displayed diminished rates of apoptosis as detected by flow cytometric analysis of propidium iodide-stained cells and terminal deoxynucleotidyltransferase-mediated fluorescein-dUTP nick end-labeling assay. While motility and phagocytosis were not affected by SHP-1C453S overexpression, adhesion and the oxidative burst in response to PMA were enhanced in the SHP-1C453S compared with those in the vector alone transfectants. Taken together, these results suggest that SHP-1 exerts an important negative regulatory influence on cell proliferation and activation while promoting spontaneous cell death in myeloid cells.

Animals↗
PubMed1999

IL-9 induces chemokine expression in lung epithelial cells and baseline airway eosinophilia in transgenic mice.

Recent data have identified IL-9 as a key cytokine in determining susceptibility to asthma. These data are supported by the finding that allergen-exposed IL-9-transgenic mice exhibit many features that are characteristic of human asthma (airway eosinophilia, elevated serum IgE and bronchial hyperresponsiveness) as compared to the background strain. A striking feature of these animals is a robust peribronchial and perivascular eosinophilia after allergen challenge, suggesting that IL-9 is a potent factor in regulating this process. In an attempt to gain insights into the molecular mechanism governing IL-9 modulation of lung eosinophilia, we investigated the ability of this cytokine to induce the expression of CC-type chemokines in the lung because of their effect on stimulating eosinophil chemotaxis. Here we show that IL-9-transgenic mice in contrast to their congenic controls exhibit baseline lung eosinophilia that is associated with the up-regulation of CC-chemokine expression in the airway. This effect appears to be through a direct action of IL-9 because the addition of recombinant IL-9 to primary epithelial cultures and cell lines induced the expression of these chemokines in vitro. These data support a mechanism for IL-9 in regulating the expression of eosinophil chemotactic factors in lung epithelial cells.

Allergens↗
PubMed1999

Magnetic resonance imaging in renal transplantation.

End stage renal disease is common and can result from a variety of diseases. The expense and morbidity of dialysis has made renal transplantation the preferred treatment when it is available. In the United States, 11,000 renal transplants are performed annually. Because of the limited supply of donor organs, every effort is made to salvage the transplanted kidney that has began to fail. Imaging modalities that are currently used to evaluate transplanted kidneys are ultrasound (US), computed tomography (CT), scintigraphy, intravenous urography (IVU), contrast angiography, and magnetic resonance imaging (MRI). MRI offers multiple advantages. MRI provides cross sectional and vascular information without the risks of ionizing radiation, iodinated contrast, or arterial catheterization. This article describes the role of MR imaging in renal transplantation, technical aspects of image acquisition, and MR findings of post-transplantation complications.

Contrast Media↗
PubMed1999

MRA contrast bolus timing with ultrasound bubbles.

The purpose of this study was to determine the feasibility of using an ultrasound contrast agent test bolus to determine optimum bolus timing for three-dimensional (3D) gadolinium (Gd)-enhanced magnetic resonance angiography (MRA). Small test doses of ultrasound contrast agent (0.3 ml Optison) were injected intravenously followed immediately by a 20 ml saline flush. Arrival of the contrast agent was detected by spectral Doppler ultrasound (US). This technique was implemented in patients undergoing peripheral vascular MRA and carotid MRA. Arrival of the US contrast agent test bolus was readily detected by the change in amplitude of the Doppler spectrum and by a huge increase in the audio signal amplitude. This contrast travel time measurement accurately guided bolus timing for 3D Gd MRA. Bolus timing for 3D contrast-enhanced MRA can be performed using US, thereby eliminating the problems and MR scanner time required for injecting a test bolus of Gd contrast.

Albumins↗
PubMed1999

Multiple DNA repair mechanisms and alkylator resistance in the human medulloblastoma cell line D-283 Med (4-HCR).

PURPOSE: We have previously reported preferential repair of DNA interstrand crosslinks in the 4-hydroperoxycyclophosphamide-resistant human medulloblastoma cell line D-283 Med (4-HCR). We now report further studies that explored the potential mechanisms underlying this repair. METHODS: Limiting dilution assays and Western, Southern, and Northern blots were used to compare specific differences between D-283 Med (4-HCR) and its parental line D-283 Med. RESULTS: D-283 Med (4-HCR) was cross-resistant to melphalan and 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU), with O6-alkylguanine-DNA alkyltransferase (AGT) levels of 466+/-164 fmol/mg protein; AGT levels in the parental line, D-283 Med, were 76+/-96 fmol/mg. The increase in AGT activity was not a result of gene amplification. Depleting AGT with O6-benzylguanine partially restored sensitivity to BCNU. Both cell lines were deficient in the human mismatch protein MutLalpha. ERCC4 mRNA and poly(ADP-ribose) polymerase levels were similar in both cell lines, and ERCC1 mRNA levels were 2- to 2.5-fold lower in D-283 Med (4-HCR). Topoisomerase I levels were 2- to 2.5-fold higher in D-283 Med compared with D-283 Med (4-HCR). CONCLUSION: These results, while illustrating the multiple differences between D-283 Med and D-283 Med (4-HCR), do not explain the enhanced DNA interstrand crosslink repair seen in D-283 Med (4-HCR).

Antineoplastic Agents, Alkylating↗
PubMed1999

Modulation of cyclophosphamide activity by O6-alkylguanine-DNA alkyltransferase.

PURPOSE: The human medulloblastoma cell line D283 Med (4-HCR), a line resistant to 4-hydroperoxycyclophosphamide (4-HC), displays enhanced repair of DNA interstrand crosslinks induced by phosphoramide mustard. D283 Med (4-HCR) cells are cross-resistant to 1,3-bis(2-chloroethyl)- -nitrosourea, but partial sensitivity is restored after elevated levels of O6-alkylguanine-DNA alkyltransferase (AGT) are depleted by O6-benzylguanine (O6-BG). Studies were conducted to define the activity of 4-HC and 4-hydroperoxydidechlorocyclophosphamide against D283 Med (4-HCR) after AGT is depleted by O6-BG. METHODS: Limiting dilution and xenograft studies were conducted to define the activity of 4-HC and 4-hydroperoxydidechlorocyclophosphamide with or without O6-BG. RESULTS: The activity of 4-HC and 4-hydroperoxydidechlorocyclophosphamide against D283 Med (4-HCR) was increased after AGT depletion by O6-BG preincubation. Similar studies with Chinese hamster ovary cells, with or without stable transfection with a plasmid expressing the human AGT protein, revealed that the AGT-expressing cells were significantly less sensitive to 4-HC and 4-hydroperoxydidechlorocyclophosphamide. Reaction of DNA with 4-HC, phosphoramide mustard, or acrolein revealed that only 4-HC and acrolein caused a decrease in AGT levels. CONCLUSIONS: We propose that a small but potentially significant part of the cellular toxicity of cyclophosphamide in these cells is due to acrolein, and that this toxicity is abrogated by removal of the acrolein adduct from DNA by AGT.

Animals↗
PubMed1999

Magnetic resonance imaging of the aorta and branch vessels.

Magnetic resonance imaging (MRI) can provide a comprehensive evaluation of the aorta and its major branches. T1-weighted spin-echo images and cine-MRI have long been known to be useful for the evaluation of congenital aortic anomalies, aortic aneurysms, and aortic dissections. Gadolinium (Gd)-enhanced three-dimensional magnetic resonance angiography (MRA) is a more recent development that affords better spatial resolution. This technique can be performed during an individual breath-hold and does not require electrocardiographic gating. The data from Gd-enhanced three-dimensional MRA, furthermore, can be used both for projectional angiographic viewing and for multiplanar reformation. In this article, MRI of the aorta and its major branches will be reviewed, with emphasis on the newer technique of Gd-enhanced three-dimensional MRA.

Aorta↗
PubMed1999

Surfactant protein A enhances alveolar macrophage phagocytosis of a live, mucoid strain of P. aeruginosa.

In this study, we investigate the interaction between surfactant protein A (SP-A) and a live, mucoid strain of Pseudomonas aeruginosa and identify a mechanism of clearance of this organism by alveolar macrophages. (125)I-labeled SP-A bound live, but not heat-killed, P. aeruginosa organisms in a concentration-dependent manner. Unlabeled SP-A bound live bacteria, protein isolated from whole organisms, and specific proteins of the P. aeruginosa outer membrane. The binding of SP-A to P. aeruginosa and outer membrane components was inhibited by either EDTA or mannose. Phagocytosis assays with fluorescent microscopy demonstrated that the percentage of macrophages with internalized FITC-labeled P. aeruginosa was increased 1.8-fold (19 vs. 35%) by pretreating the live bacteria with SP-A. This finding was confirmed by direct visualization of ingested bacteria by electron microscopy. Adhering macrophages to SP-A-coated surfaces attenuated the increased uptake of P. aeruginosa pretreated with SP-A, suggesting that SP-A acts as an opsonin to stimulate macrophage phagocytosis of this strain of P. aeruginosa.

Animals↗
PubMed1999

Surfactant protein D stimulates phagocytosis of Pseudomonas aeruginosa by alveolar macrophages.

Surfactant protein (SP)-D is an oligomeric glycoprotein belonging to the family of collagen-like lectins known as collectins, which have previously been shown to stimulate phagocytosis and other immune cell functions. The hypothesis investigated in this study was that SP-D would stimulate the phagocytosis of an important pulmonary pathogen, Pseudomonas aeruginosa. SP-D, isolated from the lavage fluid of silica-treated rats, significantly enhanced the uptake of three of six strains of P. aeruginosa by rat alveolar macrophages as analyzed by both fluorescence and electron microscopy. SP-D had only minimal effects on phagocytosis of Haemophilus influenzae. SP-D bound to live P. aeruginosa, and binding was inhibited by chelation of calcium and by a competing saccharide, inositol. In vitro killing assays demonstrated that macrophage-mediated killing of one of the mucoid strains of P. aeruginosa was modestly enhanced by SP-D. P. aeruginosa was not measurably aggregated by SP-D either macroscopically or microscopically. Further, SP-D does not appear to act as an activation ligand because adherence of macrophages to SP-D- coated slides did not stimulate the uptake of P. aeruginosa. These findings suggest that SP-D may be important in controlling the pathogenesis of P. aeruginosa in the lung.

Animals↗
PubMed1999

[The effect of vasectomy on spermatogenesis and proliferation of rat spermatogenic cell].

In order to explore the effect of vasectomy on spermatogenesis and proliferation of rat spermatogenic cell, we detected the DNA content of rat spermatogenic cells by flow cytometry at 4 weeks and 8 weeks after vasectomy. The results showed that the percentages of 1C cell group (spermatid and sperm) in the two experimental groups were apparently lower than that of the two control groups respectively (P < 0.05), but the percentage of 2C cell group (spermatogonium and spermotocyte) in the two experiment groups were much higher than those of the two control groups respectively (P < 0.05); The proliferation index (PI) of experimental groups was significantly lower than that of control groups (P < 0.05) and most of the cells in the experimental groups were on G0/G phase. The percentage of S-phase cell in the 8 weeks experimental group was obviously lower than that of the 4 weeks experimental group. These findings suggest that vasectomy in rat may affect many stages in spermatogenesis and delay the proliferation of spermatogenic cell.

Animals↗
PubMed1999

[Changes of blood circulation, muscle and skeletal systems in 30 d tail-suspended [correction of tail-suspented] rats].

OBJECTIVE: To confirm the tail-suspended rat model for the study of countermeasures against weightlessness. METHOD: The changes of blood circulation, muscle and skeletal systems in control group rats (n = 15) and 30 d tail-suspended rats (n = 15) were compared. RESULT: Compared with the control group, the hemorrheology and erythrocyte deformability decreased significantly, muscle-fiber atrophy, muscle contraction function decreased, the type I muscle fibers transformed to the type II muscle fibers, bone-mineral content of L3 and load capacity of femur declined, bone metabolism changed in the suspended rats. CONCLUSION: The tail-suspended rat is a suitable animal model for the study of countermeasures against weightlessness.

Animals↗
PubMed1999

[Leukocyte glucocorticoid receptor and its mRNA levels in leukemia patients].

OBJECTIVE: To explore factors for differentiating non-Hodgkin's lymphoma cell leukemia (NHLCL) and acute lymphoblastic leukemia (ALL). METHODS: Leukocyte glucocorticoid receptor (GR) and GR mRNA levels were measured in 22 NHLCL, 18 ALL, 10 chronic lymphocytic leukemia (CLL) patients and 6 healthy subjects by using radio-ligand binding assay and molecular hybridization using GR cDNA as the probe. RESULTS AND CONCLUSIONS: The leukocyte GR and GR mRNA levels were significantly different between NHLCL and ALL(P < 0.01), and could be used as parameters for differential diagnosis of these two types of leukemia.

Adult↗
PubMed1999

[Clinical observation on treatment of 304 patients suffered from acute myocardial infarction with integrated Traditional and Western Medicine].

OBJECTIVE: To make a retrospective survey study on clinical effect and regular pattern of TCM treatment based on Syndrome Differentiation in treating patients of acute myocardial infarction (AMI), admitted in Xiyuan Hospital from January 1978 to December 1997 with integrated traditional Chinese and western medicine. METHODS: Statistical analysis was made in the following items of 304 patients: age, sex, location of infarction, complication, cause of death, mortality, as well as TCM Syndrome, principle of treatment, prescription and medicinal herbs used. RESULTS: The incidences of complications in this group for arrhythmia, pump failure, thrombosis were 68.75%, 36.84% and 0.66% respectively, while those in patients treated with western medicine reported by literature in China were 86%-100%, 50% and 2% respectively. Mortality in this group after using thrombolytic therapy was reduced from 17.32% (35/202) to 10.78% (11/102). Types of disease, according to Syndrome Differentiation of TCM, were mainly the Qi-deficiency type, blood stasis type and turbid-phlegm type. And the principle of TCM treatment was mainly to supplement Qi, activate blood circulation and resolve phlegm. CONCLUSION: Integrated traditional Chinese and western medicine treatment of AMI could reducing incidence of complications, such as arrhythmia, pump failure and thrombosis, and thrombolytic therapy could reduce mortality of patients. The frequently encountered TCM Syndrome types and the corresponding therapeutic methods and prescriptions used in treating AMI have also been summarized in this paper.

Adult↗