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Biomedical subjects

D Du

Publications and source records attributed to D Du.

At least 19 recordsLinked to original sources
PubMed2000

[Determination of trichlosan in cosmeticy by high-performance liquid chromatography].

A method was developed for the determination of an antiseptic-trichlosan in cosmeticy by HPLC followed by diode-array detection. The chromatographic separation was performed on C18 column with a mobile phase of acetonitrile-water(60: 40, V/V) which was adjusted to pH3.0 by glacialacetic acid. The UV wavelength was 280 nm. Retention time as well as UV spectrum were used for the qualitation of trichlosan, and peak area or peak height for quantitation. The method showed good accuracy and precision average recovery of trichlosan from different cosmetics was between 91.86% and 98.83%. Relative standard deviation was between 0.72% and 2.75%.

Anti-Infective Agents, Local↗
PubMed2000

Receptor-mediated endocytosis in the procyclic form of Trypanosoma brucei.

In Trypanosomatids, endocytosis and exocytosis occur exclusively at the flagellar pocket, a deep invagination of the plasma membrane where the flagellum extends from the cell. Both bloodstream and procyclic trypanosomes are capable of internalizing macromolecules. However, structures resembling coated vesicles were only identified in bloodstream form and not in procyclic form trypanosomes. Due to the apparent absence of coated vesicles in procyclics, the significance of receptor-mediated endocytosis in procyclic trypanosomes has been considered of minimal importance. We show that the flagellar pocket associated cysteine-rich acidic transmembrane protein (CRAM) may function as an high density lipoprotein receptor in the procyclic form trypanosome. Using anti-CRAM IgG we have characterized the process of CRAM-mediated endocytosis in procyclic form trypanosomes. The wild type procyclic trypanosome binds and internalizes anti-CRAM IgG but not the non-immune IgG in a saturable and time-dependent manner; the binding and uptake of (125)I-labeled anti-CRAM IgG are inhibited by excess unlabeled anti-CRAM IgG. Uptake and degradation of anti-CRAM IgG do not occur at 4 degrees C. At 28 degrees C, the internalized anti-CRAM IgG were efficiently degraded through a process that is inhibited by incubation at 4 degrees C and sensitive to the presence of chloroquine. The uptake and degradation of anti-CRAM IgG does not occur in the CRAM null mutant cell line. These results suggested that the uptake of anti-CRAM IgG in the wild type procyclics occurs via receptor-mediated endocytosis of the CRAM protein. Deletion of the cytoplasmic extension of CRAM drastically reduced the degradation but not the binding of anti-CRAM IgG. This result indicated that potential internalization signals may be present in the cytoplasmic extension of CRAM. This is the first time that the importance of receptor-mediated endocytosis in procyclic form trypanosomes has been demonstrated.

Amino Acid Sequence↗
PubMed2000

Comparative spectroscopic and electrochemical properties of bis(octakis(dodecylthio)naphthalocyaninato)europium(III) and bis(tetra-tert-butylnaphthalocyaninato)europium(III) complexes.

Bis(substituted-2,3-naphthalocyaninato)europium(III) complexes: bis(octakis(dodecylthio)-2,3-naphthalocyaninato)europium(III) (Eu[2,3-Nc(SC12H25)8]2, 1) and bis(tetra-tert-butyl-2,3- naphthalocyaninato)europium(III) (Eu[2,3-Nc(t-Bu)4]2, 2) have been synthesized by cyclic tetramerization of naphthalonitriles with Eu(acac)3.H2O in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) in refluxing n-octanol. These compounds were characterized by UV-visible, magnetic circular dichroism (MCD), near-IR, IR, EPR, and mass spectroscopies. The absorption and MCD spectra of 1 showed splitting of the Q band, with peaks at 700 and 784 nm, red shifted from the Q band of 2 at 763 nm. The absorption and MCD spectral band deconvolution calculations of complex 1 gave two A terms in the Q-band region. The A terms are assigned to 2A2-->2E1 transitions. Cyclic voltammograms of 1 and 2 showed reversible oxidation couples at E1/2 = -0.28 V (for 2) and -0.25 V (for 1) vs ferrocenium/ferrocene (Fc+/Fc). The second oxidation exhibited a complicated behavior for both complexes. The reduction couples for 2 were observed at E1/2 = -0.61, -1.64, -1.97, and -2.42 V, and for 1 they were observed at E1/2 = -0.62, -1.60, -1.86, and -2.27 V vs Fc+/Fc. Spectral changes observed on chemical oxidation and reduction of the complexes are presented, and the behaviors of 1 and 2 are compared.

Journal Article↗
PubMed2000

[Penetrating wounds of the heart: analysis of 56 patients].

OBJECTIVE: To assess the management of penetrating cardiac injuries. METHODS: 56 patients with penetrating wounds of the heart were studied retrospectively. The study lasted for 11 years. RESULTS: Stab wounds accounted for 89.3% of the 56 patients. 56 patients underwent thoracotomy. Preoperative infusion was less than 1,000 ml in 68% of the patients. Preoperative pericardiocentesis was done only in 2 patients, of whom one was false negative. Four patients with cardiac arrest soon after arrival were subjected to emergency thoracotomy; three survived. After the operation, 2 patients died of associated abdominal injuries and failure of cerebral resuscitation. The overall survival rate was 96.4%. CONCLUSIONS: Early diagnosis and prompt thoracotomy are essential to the treatment of penetrating cardiac injuries. Preoperative massive transfusion and pericardiocentesis are not advocated.

Adolescent↗
PubMed2000

[A histopathologic and immunohistochemical study of prognostic factors in esophageal squamous cell carcinoma].

OBJECTIVE: To investigate the prognostic value of various histopathological features and expression of immuno-phenotypes in esophageal squamous cell carcinoma (ESCC). METHODS: The tumor samples from 97 primary ESCC patients with potentially curative resection were evaluated for the following parameters: tumor size, grade of differentiation, pattern of invasion, depth of invasion, degree of lymphocyte infiltration, lymph node metastasis, TNM stage and p53, EGFR, c-erbB-2, nm23, cathepsin D protein expression. The prognostic impact of these parameters were analyzed by univariate and multivariate survival analyses. RESULTS: In the univariate Kaplan Meier analysis, poor differentiation, infiltrating growth pattern, invasion reaching adventitia, absent lymphocytic infiltration, lymph node metastasis, high staging, EGFR positive expression and nm23 negative expression were all associated with lower survival rate (Log-rank test, P < 0.05, respectively). However, the multivariate Cox analysis demonstrated that only pattern of invasion (RR = 2.000), degree of lymphocyte infiltration (RR = 0.509), TNM stage (RR = 1.733), EGFR expression (RR = 1.812) and c-erbB-2 expression (RR = 2.364) were significant prognostic factors (P < 0.05, respectively). CONCLUSION: For ESCC, the pattern of invasion, degree of lymphocyte infiltration, EGFR and c-erbB-2 protein expression had independent prognostic values as well as the TNM stage. Comprehensive analysis of these parameters can be helpful to identify biological behavior of ESCC and predict more accurately the prognosis of patients with ESCC.

Adult↗
PubMed1999

The N terminus of Kaposi's sarcoma-associated herpesvirus G protein-coupled receptor is necessary for high affinity chemokine binding but not for constitutive activity.

Kaposi's sarcoma-associated herpesvirus (KSHV) contains a gene encoding a G protein-coupled receptor (KSHV-GPCR) that is homologous to mammalian chemokine receptors. KSHV-GPCR signals constitutively (in an agonist-independent manner) via the phosphoinositide-inositol 1,4,5-trisphosphate pathway. Because it has been proposed that the N terminus (N-TERM) of other GPCRs may act as tethered agonists, we determined whether the N-TERM of KSHV-GPCR is necessary for constitutive signaling activity or ligand binding, or both. We show that replacement of the entire N-TERM of KSHV-GPCR with those of two other GPCRs, deletion of residues within the N-TERM, and disruption of a putative disulfide bond that may hold the N-TERM in close proximity to extracellular loop 3 do not affect constitutive signaling activity but decrease chemokine binding. There were differences in the effects of mutation of the N-TERM on binding of the chemokines growth-related oncogene alpha, which is an agonist, and interferon-gamma-inducible protein-10, which is an inverse agonist. The effects on chemokine binding were accompanied by changes in chemokine regulation of KSHV-GPCR signaling. We conclude that the N-TERM is not necessary for constitutive KSHV-GPCR signaling, i.e. the N-TERM is not a tethered agonist, but plays a crucial role in binding of chemokine ligands and of chemokine regulation of KSHV-GPCR signaling.

Animals↗
PubMed1999

[Expression of metastasis suppressor gene nm23-H1 in oral squamous cell carcinoma and its relation to tumor prognosis].

OBJECTIVE: To study the relation between the expression level of nm23-H1 protein and prognosis of oral squamous cell carcinoma (OSCC). METHODS: The expression of nm23-H1 protein in 75 cases of OSCC, 27 cases of oral mucosa, 9 cases of cervical lymph-node metastases by immunohistochemical technique (SABC), and the relation between nm23-H1 protein expression level and prognosis of OSCC was evaluated by chi-test and single-factor, multi-factor Cox proportional hazards regression model analysis. RESULTS: These immunoreactivities of nm23-H1 protein were mostly in the cytoplasm of tumor and epithelial cells. There was a significant difference of nm23-H1 protein expression level between three-year survival and seven-year survival group (P < 0.05), and there was a relation between nm23-H1 protein expression level and prognosis of OSCC in single-factor Cox analysis. But no relation was found between nm23-H1 protein expression level and prognosis in multi-factor Cox analysis. CONCLUSION: nm23-H1 protein expression level was probably not a valuable predictor of OSCC patients' prognosis. It may indirectly affect OSCC prognosis through its effect on OSCC metastasis.

Carcinoma, Squamous Cell↗
PubMed1999

[Expression of nm23-H1 gene in oral squamous cell carcinoma and its relation to tumor metastasis].

OBJECTIVE: To make an inquiry into the relation between the expression level of nm23-H1 protein and metastasis of oral squamous cell carcinoma (OSCC). METHODS: We evaluated the expression of nm23-H1 protein in 75 cases of OSCC by immunohistochemical technique (SABC). RESULTS: These immunoreactivities of nm23-H1 protein were most common in the cytoplasm of tumor and epithelia cell. Using single-factor chi-test, we found there was a significant correlation between the expression of nm23-H1 protein and lymph node metastasis of OSCC (P < 0.01), pathology grade (P < 0.05). But no statistical association was found among nm23-H1 protein expression level and tumor size, site and patient's sex, age. Using multi-factor logistic stepwise regression analysis, we found that nm23-H1 protein expression level had more effect on OSCC cervical lymph node metastasis than any other parameters. CONCLUSIONS: The results suggested that nm23-H1 protein play an important role in the suppression of the metastasis of OSCC, and that determining the expression level of nm23-H1 protein may help us prognose the metastasis of OSCC.

Adult↗
PubMed1998

[Embolotherapy of craniofacial tumors and vascular diseases: assessing the effect of different embolic agents].

To assess the effect of different embolic agents in curing craniofacial tumors and vascular diseases, 21 patients who were treated by intra-arterial embolization were divided into three groups: gelfoams, bletilla striatas and coils. The results showed that 8 cases of preoperative patients in gelfoams group had a good effect and bleeding were reduced during operation. One patient had vascular recanalization at 1 month after embolization with gelfoam. All patients in bletilla striatas had ideal effect. In coils group, collateral supplying arteries were found in 3 patients at once after embolization and the others had a good effect. In conclusion, craniofacial tumors and vascular diseases were fit to embolotherapy. The selection of embolic agents should be gelfoam in preoperative embolization and bletilla striata in palliative treatment There were not severe complications.

Adolescent↗
PubMed1998

[The change of salivary beta 2-microglobulin concentration in normal adults].

OBJECTIVE: To understand the influence of various physiological factors on the concentration of beta 2-microglobulin in saliva. METHODS: We measured salivary beta 2-microglobulin concentration in 200 normal adults, from 21 year-old to 70 year-old, by means of radioactive immunoassay method. RESULTS: We found, that there was no significant difference between males and females in salivary beta 2-m concentration, and salivary beta 2-m concentration was more significantly elevated in the adults above 50 year-old, compared with the adults from 21 year-old to 50 year-old. We also found, that there was no significant correlation between salivary beta 2-m concentration and serum beta 2-m concentration. CONCLUSIONS: Our results suggested, that beta 2-m in saliva may be produced in oral cavity and salivary glands, and measurement of salivary beta 2-m concentration may offer a valuable method to diagnose lymphocytic infiltration disease in oral cavity or salivary glands.

Adult↗
PubMed1997

Mechanisms underlying different surface ECG morphologies of recurrent monomorphic ventricular tachycardia and their modification by procainamide.

INTRODUCTION: Distinct surface ECG morphologies (ECGMs), from one episode to the next, of recurrent monomorphic ventricular tachycardia (VT) in the same patient complicate endocardial catheter mapping and the success of ablative therapy. This study investigates the incidence and mechanisms of multiple ECGMs during recurrent monomorphic VTs in a canine model of experimental myocardial infarction (MI). METHODS AND RESULTS: Computerized ECG analysis and simultaneous endocardial and epicardial activation mapping with a 64 bipolar electrode array were used to analyze the relation between site of VT origin, local activation sequence, and surface ECGM in 72 VT episodes induced in 9 of 17 dogs with experimental MI. Pairwise comparisons of all VTs induced in the same animal were done in drug-free state (47 VTs) and after intravenous procainamide (25 VTs). In drug-free state, VT pairs with similar surface ECGMs manifested endocardial breakthrough sites (BSs) within a distance < 10 mm in 46 (100%) of 46 VT pairs compared to 43 (45%) of 95 VT pairs with different surface ECGMs (P < 0.0001). Of all 89 VT pairs with endocardial BSs within < 10 mm, similar endocardial activation patterns were found in 34 (74%) of 46 pairs with similar ECGMs in contrast to 6 (14%) of 43 pairs with different ECGMs (P < 0.001). Similar comparisons of VT pairs induced after intravenous procainamide administration showed that the endocardial BSs were located within < 10 mm in 9 (75%) of 12 VT pairs with similar and in 17 (49%) of 95 with different surface ECGMs, respectively (P = NS). CONCLUSIONS: In the same heart, similar surface ECGMs of recurrent VT are highly predictive of closely spaced endocardial BSs in drug-free state, but not after procainamide administration. Nearly half of the VTs with different surface ECGMs still originate from closely spaced endocardial BSs but commonly manifest a change in the endocardial activation spread from this site. Thus, assumptions about different mechanisms and sites of VT origin based on different surface ECGMs should be made with caution.

Animals↗
PubMed1997

[Evaluation of parotid sialography and labial salivary gland biopsy to the diagnosis of Sjögren syndrome].

OBJECTIVE: To investigate the relationship between the change of parotid sialograms and the results of labial gland biopsies in the patients with Sjögren syndrome (SS). METHODS: Parotid sialography and labial salivary gland biopsy were performed on 100 patients with Sjögren syndrome. RESULTS: The sialectasis of parotid terminal ducts was found in 87 patients, the widening only of main ducts was found in 8 patients, and 5 cases showed normal sialograms. The results of labial salivary gland biopsies showed, that 90 cases had focal lymphocytic sialadenitis (Zhen Linfan's grade score of 2), 59 cases had a score of 4 accoding to Chisholm's grading score; moderate scattered lymphocitic infiltration was shown in 10 patients. CONCLUSION: Our results suggested that the lesions of parotid gland and labial salivary gland in SS were concerted closely. Therefore a new way of combining the changes of parotid gland and labial salivary gland for the diagnose of SS was proposed.

Adolescent↗
PubMed1997

[The value of salivary beta 2 microglobulin concentration for diagnosis of Sjögren's syndrome].

In this paper we measured salivary beta 2 microglobulin (beta 2 m) concentration in 40 patients with Sjögren's syndrome, including 20 patients with systemic lupus erythematosus, 12 patients with recurrent aphthous ulceration and 16 patients with single xerostomia, and in 40 normal controls. The results showed that salivary beta 2 m concentration was more significantly elevated in Sjögren's syndrome patients, compared with that in both normals and other patients. The measurement of beta 2 m concentration in saliva may offer a simple and valuable method for diagnosis of Sjögren's syndrome.

Adult↗
PubMed1996

Erythropoietin-like activity in vivo of the fusion protein rhIL-6/IL-2 (CH925).

CH925 is a novel cytokine of a fusion protein interleukin-6 (IL-6)/IL-2 exhibiting erythropoietin (Epo)-like effects in vivo and ex vivo, in addition to its enhanced effects compared to IL-2 and IL-6 reported by us previously, which indicates its potential clinical use. Our present study was undertaken to determine the Epo-like activity of CH925 in vivo. The reticulocyte response was observed in transfusion-induced polycythemic mice by using flow cytometry with pyronin Y staining. On day 2 after injection of CH925, the average number of reticulocytes was 2.11% in the group given 250 micrograms/kg/d and 1.01% for 100 micrograms/kg/d. The mean fluorescence intensity (MFI) also significantly increased. Longitudinal studies of CH925 were performed on days 2, 4, and 10, and reticulocyte counts increased up to a peak on day 4. Activity of CH925 (100 micrograms/kg/d) corresponds to 1 U of standard rhEpo in our study.

Animals↗
PubMed1995

[The change of filtration-index of erythrocyte malonyldialdehyde and superoxide dismutase in patients with pregnancy induced hypertension].

OBJECTIVE: To observe the relationship between the filtration-index of erythrocytes and concentration of erythrocytic superoxide dismutase (SOD), plasma malonyldialdehyde (MDA) in cases of pregnancy induced hypertension (PIH). METHODS: We have measured the level of MDA and filtration-index, SOD content of erythrocytes in maternal and cord blood of 31 cases with PIH (group A) and 25 cases of normal pregnancy (group B) using TBA method, nucleopore membraned cell deformability meter and pyrogallol self-oxidizing method. RESULTS: The mean filtration-index level and erythrocytic SOD were significantly higher in group A than those of group B (P < 0.01 and P < 0.05). The mean content of plasmatic MDA in group A increased markedly (P < 0.01) compared to that of group B. There was no difference of these parameters in cord blood between group A and group B. CONCLUSION: The decrease of red cell deformability due to the increase of plasma MDA level may be the underlying mechanism of PIH.

Adult↗