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Biomedical subjects

Q He

Publications and source records attributed to Q He.

At least 217 records · Page 12Linked to original sources
PubMed1996

[The morphometric study of endometrium during long-term use of TCu220C IUD].

OBJECTIVE: To observe the pathological changes of endometrium in women using TCu220C intrauterine devices (IUD) for 5-12 years, and to judge its long term safety. METHODS: A hundred women using TCu220C IUD for 5-12 years were randomly selected as IUD group. Samples of endometrium from the sites compressed by IUD and 1 cm apart were taken under hysteroscopy during proliferative phase. Another 100 women matched in age but not IUD users served as control group, and endometriums were taken by curettage. All the samples were studied for morphometry. RESULTS: All pathological changes were localized in the areas of endometrium in direct contact with IUD but not the adjacent areas. Inflammatory reactions mainly lymphocytes infiltration were seen in all IUD samples with depth of 0.91-1.20 mm. Atrophy was seen in 25% of the cases using IUD for 5-10 years with an average area of 0.81 mm2, while in 71% of those using IUD for 10-12 years with an area of 1.50 mm2. Fibrosis was shown in 18% of the cases using IUD for 5-10 years with area of 1.87 mm2, and 100% in 10-12 years with area of 2.04 mm2. There was no hyper-proliferation and malignant changes in IUD group. Hemorrhage and necrosis existed in all cases using IUD for 10-12 years. In the IUD group all the cases showed asynchronization of endometrium. CONCLUSION: It is safe for women using TCu220C IUD for 5-12 years. Since endometrial hemorrhage and necrosis were shown in women using IUD over 10 years, it is better to remove the IUD after 10 years if they have clinical symptoms.

Adult↗
PubMed1996

[The effects of histamine H2 receptor agonist, antagonist and antineoplastic agent on the in vitro growth of PB CFU-GM from normal individuals and HL-60 leukemia cells].

Colony forming unit of granulocytes and macrophages from peripheral blood (PB CFU-GM) represents stem and/or progenitor cells from human blood. In this paper, the effects of histamine H2 receptor agonist 4-methylhistamine (4-MH) and its antagonist ranitidine (Ranit) on the growth of PB CFU-GM cultured in methylcellulose system were studied and their differential effects on normal PB CFU-GM and leukemic HL-60 cells were compared with the effect of the antineoplastic agent cytosine arabinoside (Ara-C). It was found that the histamine H2 receptor agonist 4-MH stimulated the growth of PB CFU-GM when 4-MH was added at the concentrations from 10(-9) mol.L-1 to 10(-6) mol.L-1 among which the dose 10(-8) mol.L-1 exerted most potent stimulating effect (the PB CFU-GM colony numbers was 137.68% +/- 8.20% vs the control, P < 0.01). In contrast, the antagonist Ranit showed inhibitory effect on the growth of PB CFU-GM when at the concentrations 10(-9)-10(-5) mol.L-1 cultured for 14 d in the same methylcellulose system. The inhibition rate was 23.73% +/- 1.16% (10(-9) mol.L-1) and 41.42% +/- 6.75% (10(-6) mol.L-1), respectively. Although both Ranit and Ara-C could inhibit the growth of PB CFU-GM in vitro, Ranit exerted much greater inhibition on HL-60 leukemic cells than on normal PB CFU-GM at the dose of 10(-6) mol.L-1 (100% inhibition for HL-60 and < 50% inhibition for PB CFU-GM). However, the inhibition rate of Ara-C for both HL-60 and PB CFU-GM was 100% at the intensive chemotherapeutic dose of 10(-5) mol.L-1. It would appear that the histamine H2 receptor agonist 4-MH possesses stimulating effect on the growth of PB CFU-GM similar to its effect on CFU-GM from bone marrow as documented before. It is suggested that the histamine H2 receptor antagonist Ranit has, to some extent, potential in the treatment of myeloid leukemia, especially when combined with antineoplastic agent Ara-C at suboptimal doses.

Antimetabolites, Antineoplastic↗
PubMed1996

[An experimental study on compound anisodine III for softening scar of mouse skin after burn].

OBJECTIVE: The aim of this study was to investigate the mechanism of compound anisodine (CA) III which can rapidly soften the cicatrized tissue in clinical practice. METHODS: 2 mol/L NaOH was applied onto the back of 36 mice for one minute to induce deep grade skin burn injury. After 1 week local cicatrization occurred. The mice were randomly divided into 3 groups: 1 ml saline was used in group I as control, hyaluronidase 150 U dissolved in 1 ml 2% procaine was used in group II and 0.005% CA 0.1 ml in 2% procaine 1 ml with hyaluronidase 150 U was used in group III. Subcutaneous injection once every other day for two weeks was the method of drug administration in all the 3 groups and then all the rats were euthanized. The burned skin was sectioned for HE and modified Masson's stains. RESULTS: Histopathology revealed there were epidermis proliferation, keratinization and fibrosis with disorderly arranged collagenous fibers invading into muscles and a large amount of inflammatory cells infiltrating the lesion in groups I and II. However, the skin was nearly normal in group III. CONCLUSIONS: CA III can inhibit the epidermic and collagenous proliferation, improve the tissue blood supply and have antiinflammatory effect to prevent scar formation and promote epidermic repair in the skin.

Animals↗
PubMed1996

[Progress in the study of chymase].

Chymase is a kind of serine proteinase, mainly exists in secretory granules of mast cell and extracellular interstitium. The mature enzyme is a glycoprotein comprising 226 amino acid residues, with molecular weight of 30 kD. It can be inhibited by serine proteinase inhibitors but not by angiotensin I converting enzyme inhibitors. The cDNA and genomic DNA of human chymase were cloned and sequenced. Chymase has close relations with neurogenic inflammation, extracellular matrix catabolism, control of vasoactive peptide metabolism, and so on. It plays an important role in angiotensin II formation in human heart.

Animals↗
PubMed1995

Imaging with intermolecular multiple-quantum coherences in solution nuclear magnetic resonance.

A magnetic resonance imaging technique based on intermolecular multiple-quantum coherences in solution (the correlated spectroscopy revamped by asymmetric z gradient echo detection or CRAZED experiment) is described here. Correlations between spins in different molecules were detected by magnetic-field gradient pulses. In order for a correlation to yield an observable signal, the separation between the two spins must be within a narrow band that depends on the area of the gradient pulses. The separation can be tuned from less than 10 micrometers to more than 1 millimeter, a convenient range for many applications.

Acetone↗
PubMed1995

Integration of linkage analyses and disease association studies.

The REGD procedure of the S.A.G.E. [1994] system was used to determine the mode of inheritance of the rare disease given in Problem 1. The likelihood ratio test statistic indicated that we should reject the hypotheses of dominant and recessive inheritance at the 0.01 level, so codominant inheritance was assumed. The estimated penetrance values computed from the beta estimates given by the S.A.G.E. output were 1.0, 0.7, and 0.0 for the AA, AB, and BB genotypes respectively. A sample of three markers from each chromosome was used to determine which chromosome(s) gave evidence of having loci linked to the disease locus. The lod minus 0.83 support interval, which has been shown to provide the best approximation to 95% coverage among interval estimates [Nemesure et al., in press], was obtained for each of these markers. The criterion for rejecting the hypothesis of close linkage using the support interval methodology required that the left side of the lod minus 0.83 support interval about the maximum likelihood estimate, theta, includes only values greater than theta = 0.10. This criterion suggested that chromosomes 2, 3, and 6 did not contain the disease genes. Classical lod-score linkage analysis using the usual criteria of 3.0 for linkage and -2.0 for exclusion did not result in any regions being identified. On dropping the required lod score to 1.0, chromosomes 1, 3, and 6 gave results in favor of linkage with lod scores of 1.94 (theta = 0.19), 1.20 (theta = 0.24), and 1.30 (theta = 0.23), respectively. Association studies comparing unrelated cases to unrelated controls were done for all markers on all chromosomes. Two associations were observed which were significant at the 0.05 level after adjusting for the large number of multiple comparisons being made. The strongest association observed was between allele 7 of marker 23 on chromosome 5 and the disease (chi 2(1) = 52.20, OR = 4.7) and the second strongest was between allele 8 of marker 31 on chromosome 1 (chi 2(1) = 20.10, OR = 3.4).

Chi-Square Distribution↗
PubMed1995

Proton NMR observation of the antineoplastic agent Iproplatin in vivo by selective multiple quantum coherence transfer (Sel-MQC).

We have noninvasively detected the proton signal of an antineoplastic agent Iproplatin in vivo by selective multiple quantum coherence transfer (Sel-MQC). Without isotopic labeling or chemical modification, the Sel-MQC method labels Iproplatin by its intrinsic proton multiple quantum coherences and, hence, differentiates the Iproplatin signal from the intensive overlapping resonances of lipid and lactate. This proton NMR method should also be applicable to study other drugs with appropriate spin coupling patterns.

Animals↗
PubMed1995

Single-scan in vivo lactate editing with complete lipid and water suppression by selective multiple-quantum-coherence transfer (Sel-MQC) with application to tumors.

A novel single-scan selective homonuclear multiple-quantum coherence-transfer technique, Sel-MQC, is presented that achieves lactate editing with complete lipid and water suppression. The method is suitable for studying tissues with high fat content and those subject to substantial motion. Frequency-selective excitation is employed to selectively prepare lactate into its multiple-quantum states; lipid and water are left in the single-quantum modes and eliminated by the multiple-quantum selection gradients. The efficiency of lipid suppression is monitored by a 2D Sel-MQC experiment which separates lipid and lactate along the multiple-quantum-evolution dimension. The spatial distribution of lactate can be imaged by the spectroscopic imaging version of Sel-MQC. Sel-MQC sequences were demonstrated both in phantoms and in vivo, using subcutaneously implanted murine EMT6 tumors.

Animals↗
PubMed1995

Glucose entry into rat mesangial cells is mediated by both Na(+)-coupled and facilitative transporters.

Since previous studies from our laboratory have demonstrated that increased glucose consumption by cultured rat mesangial cells is accompanied by an accelerated production of type IV and type VI collagen, we have now examined the manner by which glucose is transported into these cells. A progressive stimulation of glucose uptake by the mesangial cells was observed with increasing concentrations of NaCl so that at 145 mmol/l about twice as much glucose entered the cells as in its absence (substituted by choline chloride). Moreover, since phlorizin inhibited the NaCl-promoted uptake of glucose and this salt was found to increase the accumulation of alpha-methylglucoside in a manner which could not be duplicated by KCl or mannitol, both Na(+)-coupled and facilitative glucose transporters appeared to be present in the cells. Km values of 1.93 mmol/l and 1.36 mmol/l were determined for the co-transport and facilitated transport pathways, respectively, with their Vmax being 29.5 and 18.0 nmol.mg protein-1.h-1. Both uptake activities were found to be down-regulated by exposure of the cells to high glucose and furthermore the Na(+)-dependent transport could no longer be detected after about 12 passages of the cells. Hybridization of mesangial cell mRNA with cDNA probes revealed transcripts for the Na+/glucose co-transporter as well as GLUT1 and to a lesser extent GLUT4.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Effect of high glucose on formation of extracellular matrix components by cultured rat heart endothelial cells.

In an attempt to define the basis for the microvascular changes observed in diabetic myocardium, a study was undertaken on the effect of elevated glucose on the synthesis by rat heart endothelial cells of the extracellular matrix components, types VI, IV and I collagen, as well as fibronectin. Confluent cultures of these cells, isolated by fluorescence-activated cell sorting after treatment with rhodamine-labelled acetylated low density lipoprotein, showed a three to fivefold enhancement in the synthesis of type VI collagen after exposure for 48 h to high glucose (20 to 30 mmol/l), as determined by immunoblot analysis. Increased production of type IV collagen and fibronectin was also observed, but the change was smaller and no effect on type I collagen was found. Measurement of mRNA levels by hybridization with cDNA probes indicated that 48-h exposure to high glucose significantly increased the level of transcripts for type VI and IV collagens but not for type I collagen. While glucose consumption by endothelial cells in high glucose doubled in the initial 24-h period, utilization returned to normal by 48 h, concomitant with a reduction in GLUT1 transcript levels, suggesting that signals for stimulation of collagen synthesis must be active during the initial period of exposure to elevated glucose levels.

Animals↗
PubMed1995

Isolation of rat heart endothelial cells and pericytes: evaluation of their role in the formation of extracellular matrix components.

In order to facilitate investigation of the cells responsible for overproduction of type VI collagen in the extracellular matrix surrounding the capillaries of diabetic rat myocardium, procedures have been developed for the isolation from this tissue of endothelial cells as well as a cell type identified as pericytes. This was accomplished by enzymatic and mechanical disruption of ventricles from young rats (125 g) followed by removal of myocytes through their nonadherence to tissue culture surfaces. Endothelial cells were separated by fluorescence-activated cell sorting after staining with rhodamine-labeled acetylated low density lipoprotein and were identified by their monolayer growth pattern, reaction with anti-von Willebrand factor and the ability to form capillary-like tubes induced by low serum concentration. Pericytes were purified by selective scraping for removal of other cell types and were identified by their irregular shape, overlapping growth pattern at confluence, reaction with anti-smooth muscle actin and content of GLUT4 glucose transporter. Fibroblasts, visualized after staining with rhodamine-labeled alpha 2-macroglobulin, were only rarely detected. Analysis of collagen by immunoblotting indicated formation by both cell types of alpha 1(IV) collagen as well as the three subunits of type VI (alpha 3 at 205 kDa and alpha 1 plus alpha 2 at 150 kDa). Both endothelial cells and pericytes demonstrated transcripts for types VI, IV and I collagen, as well as fibronectin, but while the level of the mRNA for type IV collagen was higher in pericytes than in endothelial cells, the reverse was true for collagens VI and I and fibronectin. These observations suggest that both endothelial cells and pericytes contribute to formation of the myocardial capillary matrix, but that changes involving only type VI collagen, such as occur in diabetic cardiomyopathy, may reflect a response primarily of endothelial cells.

Animals↗
PubMed1995

The perioperative use of ceftriaxone as infection prophylaxis in neurosurgery.

An open label study was conducted in the department of neurosurgery, Beijing Tiantan Hospital in China to determine the incidence of postoperative infections following the use of one or two doses of ceftriaxone administered perioperatively. A total of 343 patients, who required neurosurgery and had satisfied the inclusion criteria, was recruited during a 12 month study period. Of these 343 patients, there were 97 and 107 cases of malignant and benign tumours, respectively, 52 cases of aneurysm, 34 cases of arteriovenous malformation, and 53 other cases who underwent neurosurgery for drainage of sub-dural haematoma, relief of cerebral oedema and other indications. A total of 6 (1.75%) cases of postoperative infection was observed, of which 4 were found in the malignant tumour group, and 2 in the arteriovenous malformation group. All six patients were suffering from meningitis. During the 12 month period immediately prior to the present study, when postoperative penicillin and gentamicin was administered twice daily for 5-7 days as regular prophylaxis against infection, the incidence of postoperative infection was 7.2% in the same department managed by the same staff. Results of our present study suggest that one to two doses of ceftriaxone administered perioperatively are effective in reducing the rate of postoperative infections.

Adult↗
PubMed1995

Monoclonal antibodies to CD44 and their influence on hyaluronan recognition.

Antibodies to CD44 have been used to inhibit a variety of processes which include lymphohemopoiesis, lymphocyte migration, and tumor metastasis. Some, but not all, CD44-mediated functions derive from its ability to serve as a receptor for hyaluronan (HA). However, sites on CD44 that interact with either ligands or antibodies are poorly understood. Interspecies rat/mouse CD44 chimeras were used to analyze the specificity of 25 mAbs and to determine that they recognize at least seven epitopes. Amino acid substitutions that resulted in loss of antibody recognition were all located in the region of homology to other cartilage link family proteins. While at least five epitopes were eliminated by single amino acid replacements, multiple residues had to be changed to destroy binding by other antibodies. One antibody was sensitive to changes in any of three separate parts of the molecule and some antibodies to distinct epitopes cross-blocked each other. Certain antibodies had the ability to increase HA binding by lymphocytes but this did not correlate absolutely with antibody specificity and was only partially attributable to CD44 cross-linking. Antibodies that consistently blocked HA recognition were all sensitive to amino acid changes within a short stretch of CD44. Such blocking antibodies interacted with CD44 more strongly than ligand in competition experiments. One large group of antibodies blocked ligand binding, but only with a particular cell line. This detailed analysis adds to our understanding of functional domains within CD44 and requirements for antibodies to influence recognition of one ligand.

Amino Acid Sequence↗
PubMed1995

Decreased thymidine kinase levels in peripheral blood cells from HIV-seropositive individuals: implications for zidovudine metabolism.

Azidothymidine (zidovudine, AZT) used for treatment of HIV infection blocks the viral reverse transcriptase after phosphorylation by cellular enzymes. The first step in this reaction is the formation of AZT monophosphate, primarily catalyzed by host cytoplasmatic thymidine kinase (TK1). The activity of TK1 was determined in extracts of PHA-stimulated peripheral blood mononuclear cells (PBMCs) from 20 healthy volunteers and 49 HIV-infected patients at different stages of disease. In both groups we found a large intra- and interindividual variation of TK activity. Because TK1 expression is cell cycle regulated the proportion of stimulated cells was determined in the samples and the median thymidine kinase activity calculated. It was 3.0 pmol/mg/min x % S phase in the HIV-seronegative group and 1.1 pmol/mg/min x % S phase in HIV-infected individuals. The difference in thymidine kinase activity is statistically significant (p = 0.0001). The concentration of TK1 protein in the same extracts was also determined by immunoblotting. A positive correlation (r = 0.74) was observed between TK activity and amount of TK1 protein. The reason for this downregulation of TK is still unknown but may be related to the anergy observed in lymphocytes from HIV-infected persons. The reduced capacity for intracellular phosphorylation of AZT in HIV-infected individuals may be an important factor in the emergence of clinical AZT resistance and should also be accounted for in testing AZT resistance in vitro with PBMCs from healthy blood donors.

Antiviral Agents↗
PubMed1995

A new method to localize brain nuclei for surgery in extrapyramidal disease.

A CT localization method to be used with the Leksell stereotactic system was employed to locate the ventral lateral nucleus of the thalamus (VL) and globus pallidus (GP) for treating extrapyramidal disease (EPD). The study comprised 100 normal adults and 70 cases of EPD, and results in both populations were compared. The 70 cases of EPD were studied ventriculography, and 30 normal adults were studied my MRI. Results indicate the accuracy of localization of the primary targets was 94.25% with the CT localization method described herein and 88.9% in the control group. In conclusion, the new CT localization method is a valuable technique to locate brain nuclei and to replace ventriculography with stereotactic surgery in the treatment of EPD patients.

Adolescent↗