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Biomedical subjects

M Dong

Publications and source records attributed to M Dong.

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

[Measurements of interleukin-6, interleukin-8 and transforming growth factor-beta 1 levels in peritoneal fluid of patients with endometriosis].

OBJECTIVE: To investigate the role of cytokines in peritoneal fluid on pathogenesis of endometriosis (EM). METHODS: Interleukin-6 (IL-6), interleukin-8(IL-8) and transforming growth factor-beta 1 (TGF-beta 1) contents in peritoneal fluid (PF) of 31 cases with EM were detected by enzyme linked immunoabsorbent assay (ELISA) and compared with the counterparts of 22 cases without EM (controls). The correlation analyses between cytokine concentrations in peritoneal fluid of EM patients and the severity of EM or dysmenorrhea score were performed. RESULTS: The peritoneal fluid from patients with EM contained significantly greater amounts of IL-6 [(1.8 +/- 0.4) ng/L] and IL-8 [(1.7 +/- 0.5) ng/L] than those in controls [(1.2 +/- 0.2) ng/L and (1.4 +/- 0.3) ng/L respectively, P < 0.05]. However, in the amounts of TGF-beta 1 there were no significant difference (P > 0.05) between the two groups. The highest PF IL-6 and IL-8 concentrations were found in stage II, III and stag I, II EM respectively. A significant correlation between PF IL-6 content and the severity of disease was noted but there were no evidences of a relationship between concentrations of IL-8 and TGF-beta 1 and the severity of EM as well as between concentrations of three cytokines and dysmenorrhea score. CONCLUSION: Unusual levels of IL-6 and IL-8 in PF of EM patients partly account for imbalance of the immunologically dynamic environment in peritoneal cavity of EM patients.

Adult↗
PubMed2000

[Analysis for the titer of plasma antibody to heat stress protein 70 in workers exposed to benzene].

OBJECTIVE: To explore the titer of plasma antibody against heat stress protein 70 (HSP70) in workers exposed to benzene and its possible relationship to their health. METHODS: Forty-two workers exposed to more than 40 mg/m(3) of benzene were selected as a high exposure group, 50 of workers exposed to less than 40 mg/m(3) as a low exposure group, and 42 unexposed as a control group. Their plasma antibody against HSP70 was determined with enzyme-linked immunosorbent assay (ELISA). Analysis was conducted to study the relationship between it and other factors. RESULTS: Proportion of plasma positive antibody to HSP70 with a titer of 1:20 was significantly higher in high exposure group (26.2%) than that in controls (9.5%). Moreover, prevalence of adverse symptoms and positive signs, and level of lipid peroxide were all significantly higher in high exposure group with positive antibody to HSP70 than those with negative antibody. CONCLUSION: It was concluded that the titer of plasma antibody to HSP70 had close relation with the health of workers exposed to benzene.

Adult↗
PubMed2000

[Image and quantity analysis of blood-gas in rabbit's artery and Na(+)-K(+)-ATPase in their lungs during PE-SWD treated by HFJV].

This study was made to gain an insight into the mechanism of high-frequency jet ventilation(HFJV) treatment for the pulmonary edema after seawater drowning(PE-SWD). PaO2, PaCO2 and oxygen saturation (SaO2) of the rabbit and Na(+)-K(+)-ATPase in the rabbit's lungs in three groups--PE-SWD group(PE-SWD-G), HFJV group (HFJV-G) and control group(CG), were measured and analysed by the blood-gas analyser and computer image system. The results showed that, after 100 minutes' HFJV, the PaO2, SaO2 and the activity of Na(+)-K(+)-ATPase in the lung capillary endothelial cells in HFJV-G were significantly higher than those in PE-SWD-G(P < 0.01 or P < 0.05). Three parameters of Na(+)-K(+)-TAPase(G1, D1 and D2) in HFJV-G almost returned to their values in CG. The authors suggest that the increase of PaO2 and SaO2 in the rabbit's artery blood in HFJV-G is closely related to the rehabilitation of Na(+)-K(+)-ATPase activity in the lungs after HFJV. The mechanism of successful HFJV treatment for PE-SWD is that HFJV can better correct hypoxemia and improve the rehabilitation of Na(+)-K(+)-ATPase activity in the rabbit's lungs.

Animals↗
PubMed1999

Identification of an interaction between residue 6 of the natural peptide ligand and a distinct residue within the amino-terminal tail of the secretin receptor.

Photoaffinity labeling is a powerful tool for the characterization of the molecular basis of ligand binding. We recently used this technique to demonstrate the proximity between a residue within the carboxyl-terminal half of a secretin-like ligand and the amino-terminal domain of the secretin receptor (Dong, M., Wang, Y., Pinon, D. I., Hadac, E. M., and Miller, L. J. (1999) J. Biol. Chem. 274, 903-909). In this work, we have developed another novel radioiodinatable secretin analogue ([Bpa6,Tyr10]rat secretin-27) that incorporates a photolabile p-benzoyl-L-phenylalanine (Bpa) residue into position 6 of the amino-terminal half of the ligand and used this to identify a specific receptor residue proximate to it. This probe specifically bound to the secretin receptor with high affinity (IC50 = 13.2 +/- 2.5 nM) and was a potent stimulant of cAMP accumulation in secretin receptor-bearing Chinese hamster ovary-SecR cells (EC50 = 720 +/- 230 pM). It covalently labeled the secretin receptor in a saturable and specific manner. Cyanogen bromide cleavage of this molecule yielded a single labeled fragment that migrated on an SDS-polyacrylamide gel at Mr = 19,000 that shifted to 10 after deglycosylation, most consistent with either of two glycosylated fragments within the amino-terminal tail. By immunoprecipitation with antibody directed to epitope tags incorporated into each of the two candidate fragments, the most distal fragment at the amino terminus was identified as the domain of labeling. The labeled domain was further refined to the first 16 residues by endoproteinase Lys-C cleavage and by cyanogen bromide cleavage of another receptor construct in which Val16 was mutated to Met. Radiochemical sequencing of photoaffinity-labeled secretin receptor fragments established that Val4 was the specific site of covalent attachment. This provides the first residue-residue contact between a secretin ligand and its receptor and will contribute substantially to the molecular understanding of this interaction.

Amino Acid Sequence↗
PubMed1999

The relationship between affect expression and affect recognition in schizophrenia.

To examine the relationship between affect expression and affect recognition, we assessed 30 clinically stable, medicated schizophrenic inpatients. Affect expression was assessed using both a standard clinical rating scale (SANS) and a computerized acoustic voice analysis (VOXCOM). Affect recognition was assessed using the Florida Affect Battery (FAB). The schizophrenics' performance on the FAB was impaired, indicating broad deficits in affect recognition (p<0.05). There were no significant correlations between measures of affect expression and affect recognition, suggesting that the expressive impairment in schizophrenia is not related to their ability to discern emotions in others. SANS Inappropriate Affect, however, was negatively correlated with facial affect recognition (p = 0.001), suggesting that raters' impression of inappropriate affect may indicate a failure in the process of affect attunement.

Adult↗
PubMed1999

Expression and characterization of HIV type 1 envelope protein associated with a broadly reactive neutralizing antibody response.

We have studied envelope protein from a donor with nonprogressive HIV-1 infection whose serum contains broadly cross-reactive, primary virus NA. DNA was extracted from lymphocytes, which had been collected approximately 6 and 12 months prior to the time of collection of the cross-reactive serum, and env genes were synthesized, cloned, expressed on pseudoviruses, and phenotyped in NA assays. Two clones from each time point had identical V3 region nucleotide sequences, utilized CCR5 but not CXCR4 for cell entry, and had similar reactivities with reference sera. Analysis of the full nucleotide sequence of one clone (R2) demonstrated it to be subtype B and have normal predicted glycosylation. R2 pseudovirus was compared with others expressing env genes of various clades for neutralization by sera from U.S. donors (presumed or known subtype B infections), and from individuals infected with subtypes A, C, D, E, and F viruses. Neutralization by the U.S. sera of R2 and other clade B pseudoviruses was low to moderate, although R2 was uniquely neutralized by all. R2 was neutralized by 3/3, 3/3, 2/5, 5/8, and 3/4 clade A, C, D, E, and F sera, respectively. R2 and a clade E pseudovirus were neutralized by largely complementary groups of sera, potentially defining two antigenic subgroups of HIV-1. The results suggest that the epitope(s) that induced the cross-clade reactive NA in donor 2 may be expressed on the R2 envelope.

Amino Acid Sequence↗
PubMed1999

Structurally related peptide agonist, partial agonist, and antagonist occupy a similar binding pocket within the cholecystokinin receptor. Rapid analysis using fluorescent photoaffinity labeling probes and capillary electrophoresis.

The molecular basis of ligand binding to receptors provides important insights for drug development. Here, we explore domains of the cholecystokinin (CCK) receptor that are critical for ligand binding, using a novel series of fluorescent photolabile probes, receptor proteolysis, and rapid high resolution separation of peptide fragments by capillary electrophoresis. Each probe incorporated the same fluorophore and a photolabile p-benzoylphenylalanine at the amino terminus of the pharmacophoric domain (residue 24 of CCK-33) of CCK analogues representing full agonist, partial agonist, and antagonist of this receptor. Each was used to label the CCK receptor expressed on Chinese hamster ovary-CCKR cells, with the labeled domain then released by cyanogen bromide cleavage. Capillary electrophoresis with laser-induced fluorescence detection achieved an on-capillary mass sensitivity of 1.6 attomoles (10(-18) mol), with an excellent signal-to-noise ratio. Each of the biologically divergent, but structurally similar probes saturably and specifically labeled the same receptor domain, consistent with conservation of "docking" determinants. This had an apparent mass of 2.9 kDa, most consistent with the first extracellular loop domain. An additional probe having its site of covalent attachment in a different region of the probe (residue 29 of CCK-33) labeled a distinct receptor fragment with differential migration on capillary electrophoresis (third extracellular loop). Identification of the specific receptor residue(s) covalently linked to the amino-terminal probes must await further fragmentation and sequence analysis.

Amino Acid Sequence↗
PubMed1999

Demonstration of a direct interaction between residue 22 in the carboxyl-terminal half of secretin and the amino-terminal tail of the secretin receptor using photoaffinity labeling.

An understanding of the molecular basis of hormonal activation of receptors provides important insights for drug design. Toward this end, intrinsic photoaffinity labeling is a powerful tool to directly identify the ligand-binding domain. We have developed a new radioiodinatable agonist ligand of the secretin receptor that incorporates a photolabile p-benzoyl-L-phenylalanine (Bpa) into the position of Leu22 and have utilized this to identify the adjacent receptor domain. The rat [Tyr10,Bpa22]secretin-27 probe was a fully efficacious agonist, with a potency to stimulate cAMP accumulation by Chinese hamster ovary SecR cells similar to that of natural secretin (EC50 = 68 +/- 22 pM analogue and 95 +/- 25 pM secretin). It bound specifically and with high affinity (Ki = 5.0 +/- 1.1 nM) and covalently labeled the Mr = 57,000-62,000 secretin receptor. Cyanogen bromide cleavage of the receptor yielded a major labeled fragment of apparent Mr = 19,000 that shifted to Mr = 9,000 after deglycosylation. This was most consistent with either of two glycosylated domains within the amino-terminal tail of the receptor. Immunoprecipitation with antibody directed to epitope tags incorporated into each of the candidate domains established that the fragment at the amino terminus of the receptor was the site of labeling. This was further localized to the amino-terminal 30 residues of the receptor by additional proteolysis of this fragment with endoproteinase Lys-C. This provides the first direct demonstration of a contact between a secretin-like agonist and its receptor and will contribute a useful constraint to the modeling of this interaction.

Amino Acid Sequence↗
PubMed1999

Comparative significance of p53 and WAF/1-p21 expression on the efficacy of adjuvant chemotherapy for resectable invasive ductal carcinoma of the pancreas.

p53 tumor-suppressor gene has a dual role as a trigger of apoptosis and as an initiator of DNA repair. The cyclin-dependent kinase inhibitor WAF/1-p21 is induced by wild-type p53 and has been implicated as a downstream mediator of the growth-suppressing and apoptosis-promoting function of wild-type p53, suggesting an impact on the effectiveness of chemotherapy. This study was designed to assess the significance of p53 and WAF/1-p21 expression in the prognosis of patients and the efficacy of adjuvant chemotherapy for resectable invasive ductal carcinoma (IDC) of the pancreas. A total of 58 patients with primary IDC of the pancreas underwent pancreatectomy between 1982 and 1996: 28 patients underwent surgery alone, and 30 patients received postsurgical adjuvant chemotherapy. p53 and WAF/1-p21 were stained immunohistochemically with anti-p53 monoclonal antibody (mAb) and anti-WAF/1-p21 mAb. p53 was positively expressed in 29 (50%) of 58 primary lesions, and p21 was expressed in 24 (41%) lesions; however, p21 expression did not necessarily correlate with p53 expression. The survival curve of the patients with p53(+) IDC was significantly lower than that of those with p53(-) IDC, and p21(+) patients showed a higher survival curve than did p21(-) patients, but this difference was not statistically significant. When p53 and p21 expression were analyzed in combination, the patients with p53(+)p21(-) IDC were found to have a significantly poorer prognosis than others. On the other hand, the survival curve of the adjuvant chemotherapy group was also higher than that of the surgery-alone group, but this difference was not significant. In a multivariate analysis, p21 expression was a significantly low risk factor for death due to IDC overall, and adjuvant chemotherapy was found to decrease the risk of death from IDC in p53(+) patients. Evaluation of expression of p53 and WAF/1-p21 may be beneficial in the prediction of the patient's prognosis as well as prediction of the effects of adjuvant chemotherapy in pancreatic cancer patients.

Adult↗
PubMed1999

3-Geranyl-4-hydroxy-5-(3'-methyl-2'-butenyl)benzoic acid as an anti-inflammatory compound from Myrsine seguinii.

Bioassay-guided isolation of anti-inflammatory compounds from the methanol extract of Myrsine seguinii yielded an anti-inflammatory compound (1). The structure of compound 1 was elucidated to be 3-geranyl-4-hydroxy-5-(3'-methyl-2'-butenyl)benzoic acid on the basis of its spectroscopic data. Compound 1 strongly suppressed 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced inflammation on mouse ears at a dose of 500 micrograms (inhibitory effect (IE): 65%). The acetate and the methyl ether of 1 showed moderate activity at a 500-microgram application, with IE 38% and 27%, respectively. However, the methyl ester and the dimethyl derivative of 1 did not show activity at the same dose. The related compounds of 1, o-, m- and p-hydroxybenzoic acids also did not exhibit notable activity. These results indicate that the carboxylic acid and lipophilic terpene moieties of 1 were significant structural features for anti-inflammatory activity.

Animals↗
PubMed1999

[Study on the relationship between epidermal growth factor and fetal growth retardation].

OBJECTIVE: To evaluate the significance of epidermal growth factor (EGF) in the development of fetal growth retardation (IUGR). METHODS: EGF concentrations in amniotic fluid, maternal and fetal blood from 86 pregnant women in the third-trimester were determined by radioimmunoassay (RIA). These subjects were divided into control, large-for gestational age (LGA) group and IUGR group according to neonatal birth weights. EGF concentrations in blood samples taken from umbilical vein and artery of 11 controls were also analyzed. RESULTS: No significant differences of EGF concentrations existed in amniotic fluid, maternal and fetal blood between control and LGA group (P > 0.2 for all). Compared to the control, EGF concentration of IUGR group in amniotic fluid decreased but those in maternal and fetal blood increased significantly (P < 0.05 for all). EGF concentration of cord serum in IUGR group was significantly higher than that in LGA group (P < 0.05), but no differences of EGF levels in amniotic fluid and maternal blood existed between the two groups (P > 0.05, for all). EGF in blood samples taken from umbilical vein and artery were at the same level (P > 0.1). CONCLUSIONS: EGF in amniotic fluid, maternal and fetal blood may originate from different sources, and EGF may play a role in the development of IUGR.

Adult↗
PubMed1999

[The expression of ICAM-1 on the keratinocytes in second degree human burn skin].

OBJECTIVE: To investigate the significance of changes in intercellular adhesion molecule-1 (ICAM-1) expression on keratinocytes(KCs) during wound healing of second degree burn. METHODS: With immunohistochemistry technique, the ICAM-1 expression in second degree burn wounds in patients were investigated at four different postburn periods. The normal skins from 6 burn patients (BNG), the normal skins from 8 healthy volunteers (HVG) and the scar tissues (SG) from 8 patients served as controls. RESULTS: There was poor expression of ICAM-1 on basal cells in normal skins of healthy volunteers, while the expression of ICAM-1 enhanced in normal skins of burn patients. On basal cells in second degree burn wounds, the expression of ICAM-1 slightly increased in the first week postburn, obviously enhanced in the second week, and in the third or fourth week, the expression continued to keep strong. In addition, the ICAM-1 in KCs showed polar distribution, and the expression of ICAM-1 markedly enhanced on the multilayer KCs in neogenetic epithelium and the positive cells arranged columnarly. CONCLUSION: The enhanced expression of ICAM-1 on KCs in second degree burn wounds might be related to invasion of inflammatory cells beneath wound. It might play a role in inducing proliferation and migration of KCs and accelerating epithelization.

Burns↗
PubMed1999

[The effect of insulin-like growth factor I and insulin on intrauterine fetal growth retardation].

OBJECTIVE: To evaluate the role of insulin-like growth factor I (IGF-I) and insulin (Ins) in the occurrence of intrauterine fetal growth retardation (IUGR). METHODS: The study group included 17 women with IUGR, and 38 normal third trimester pregnant women were served as control. Maternal venous blood samples were collected from all cases before cesarean section. Umbilical venous blood and amniotic fluid were collected at the time of operation. The concentrations of Ins were measured by radioimmunoassay and concentrations of IGF-I were assayed by ELISA. RESULTS: The maternal serum IGF-I in IUGR group (117.29 micrograms/L) was significantly lower than that in the control group (207.07 micrograms/L) (P < 0.002). The umbilical serum IGF-I in IUGR group (16.73 micrograms/L) was significantly lower than that in the control (44.89 micrograms/L) (P < 0.001). There was no significant difference of maternal serum Ins between IUGR group (12.18 mIU/L) and control group (7.13 mIU/L). CONCLUSIONS: The change of IGF-I and Ins levels in maternal and umbilical serum may play an important role in the pathophysiological changes in IUGR.

Adult↗
PubMed1999

Effects of the configuration of a multi-epitope chimeric malaria DNA vaccine on its antigenicity to mice.

OBJECTIVE: Four B and Th cell epitopes were selected from conservative domain of Plasmodium falciparum antigens to construct two groups of chimeric malaria DNA vaccines with different configurations and their antigenicities were studied. METHODS: The partially synthesized oligonucleotide was annealed, PCR amplified and cloned into a mammalian cell expression vector. By using a pair of isocaudamers on the vector, different single copies of B epitopes were multiplied and were tenderly stringed into two groups of chimeric DNA vaccine with different configurations. BALB/c mice were immunized with these DNA plasmids by either intramuscular or intradermal injections. RESULTS: The antisera from the immunized mice tested by ELISA showed that only the configuration which had a single copy of universal T helper cell epitope, CS. T3, located at the C terminal of the multi-copy B cell epitopes induced a high antibody response. The T helper cell epitope at any other position of the peptide, or the double T helper cell epitopes configured with the B cell epitopes did not enhance antibody response, and some configurations even decreased the humoral response to a B cell epitope. CONCLUSION: This study demonstrated that both combination and configuration of the epitope may affect the antigenicity of a chimeric multiple antigen.

Animals↗
PubMed1999

[Immunohistochemical study of safe resection margin in the surgical treatment of laryngeal carcinoma].

OBJECTIVE: To study safe resection margin of laryngectomy according to the level of protein of gene expression. METHOD: Using citric-LSAB-immunochemical technique, the expressions of ras, c-myc and P53 were studied in different regions of larynx including 30 cases laryngeal carcinoma, border area, adjacent mucosa which was 0.5, 1.0, 1.5, 2.0 cm away from cancer and four normal laryngeal mucosa. RESULT: The results showed that both single expression and co-expression of p21, p62 and p53 increased as tissue progressed in sequence from normal mucosa, 2.0, 1.5, 1.0, 0.5 cm distant mucosa adjacent to carcinoma, border area and carcinoma. A significant different expression in most of them can be seen at regions of 0.5 cm and 1.0 cm distant from the tumor (P < 0.05). CONCLUSION: The tissue 0.5 cm adjacent to the tumor should be regarded as precancerous lesion. It is appropriate to regard 0.5 cm away from tumors as resection margins for surgical treatment of laryngeal carcinoma.

Adult↗
PubMed1999

[The clinic features of human immunodeficiency virus (HIV) on ear, nose, throat head and neck].

OBJECTIVE: To identify the clinic features of HIV infection on ENT-Head and neck area and to explore its treatment. METHOD: 68 HIV cases in zambia were analysed. RESULT: The ages of the patients are from 3 months to 46 year old. Among them 12 cases with Lump of neck, 9 with ulcer of oral-pharynx, 9 with parctid gland enlarged, 2 with submaxillary plleymon, 5 with nasal bleeding, 17 with purulent otitis Media, 4 with atrophic rhinitis. 18 cases in 58 HIV patients had tubericulosis, diarhea and anemia. 51 cases improved after treatment while 15 cases didn't improve and 2 died. CONCLUSION: It is very important to find and treat HIV patients and to prevent transmission as early as possible.

Adolescent↗
PubMed1999

[Wavelet application to reduction of stimulus artifact in transient evoked otoacoustic emissions testing].

Otoacoustic emissions(OAEs) are presently considered as an objective clinical test for assessing the integraity of peripheral hearing. Owing to the adding of the reflex waves of the stimuli, recordings of emissions evoked in response to transient stimuli are contaminated by an initial artifact, which inhibits the examination of high frequency cochlear responses that have short latencies. So OAEs testing is of serious limitation in most clinical environments. We propose an artifact reduction technique based on discrete wavelet transform pre-processing method and demonstrate empirically that the method not only improves artifact reduction but also enhances signal-to-noise ratio in the response region.

Acoustic Stimulation↗