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Biomedical subjects

X Yang

Publications and source records attributed to X Yang.

At least 685 records · Page 38Linked to original sources
PubMed1998

Human carotid arteries: correlation of intravascular US with angiographic and histopathologic findings.

PURPOSE: To establish the intravascular ultrasound (US) morphology of the arterial wall in various segments of the carotid artery and to evaluate atherosclerotic changes correlated with angiographic and in vitro histopathologic findings. MATERIALS AND METHODS: A total of 67 carotid arteries were imaged with a 3.5-F, 30-MHz intravascular US catheter: Twenty-four arteries were studied in vivo in 22 patients during neuroendovascular interventional procedures, in situ in 10 cadaveric arteries, and in vitro in 33 fresh excised arteries. RESULTS: In vivo, none of 10 calcifications and five (29%) of 17 intimal thickenings detected at intravascular US were seen at contrast material-enhanced angiography. At intravascular US, the arterial wall morphology was consistently three layered in the internal carotid artery above the bulb, either vaguely three layered or homogeneous in the bulb and in the carotid bifurcation, and homogeneous in the majority of common carotid arteries. The medial-adventitial interface was distinct in 21 (88%) of 24 arteries in vivo. Histopathologic and intravascular US classifications of the plaque agreed for 31 (82%) of the 38 arterial specimens in vitro. CONCLUSION: In vivo intravascular US was feasible in carotid arteries with mild atherosclerosis and often revealed intimal thickenings and concentric plaques in angiographically normal segments.

Adult↗
PubMed1998

Blockade of growth hormone receptor shedding by a metalloprotease inhibitor.

GH, an important growth-promoting and metabolic hormone, exerts its biological effects by interacting with cell surface GH receptors (GHRs). The GHR is a single membrane-spanning protein that binds GH via its extracellular domain. The high affinity GH-binding protein (GHBP), which corresponds to a soluble form of the GHR extracellular domain, carries a substantial fraction of the GH in the circulation of various species and probably has a role in modulation of the hormone's bioavailability. Although in rodents, it is believed that the GHBP is largely derived by translation of an alternatively spliced GHR messenger RNA, in humans and rabbits, proteolytic cleavage of the membrane-anchored receptor releases the GHR extracellular domain, which is believed to thereby become the GHBP. In this study, we used human IM-9 lymphocytes and GHR antibodies to study this proteolytic shedding of the GHBP. As determined by immunoblotting with anti-GHR cytoplasmic domain serum, addition of phorbol 12-myristate 13-acetate (PMA; 1 microg/ml) to serum-starved cells led to rapid loss (roughly 60% decline after 1 h; t(1/2) = approximately 5 min) of mature GHRs (115-140 kDa) from either total cell or detergent-soluble extracts. Loss of full-length GHRs was accompanied by accumulation of four proteins (65-68 kDa), each reactive with the cytoplasmically directed antiserum. The pattern of appearance of these GHR ctyoplasmic domain proteins, the electrophoretic and immunological characteristics of which are similar to those of a recombinant rabbit GHR mutant that lacks the extracellular domain, was such that progressively faster migrating forms were evident between 5-60 min of PMA exposure. Treatment with N-ethylmaleimide (NEM; 5 mM), an agent known to cause GHBP shedding from IM-9 cells, promoted a similar rapid loss of full-length GHRs and an accumulation of GHR cytoplasmic domain remnant proteins. PMA-induced, but not NEM-induced, GHR proteolysis was blocked by the protein kinase C inhibitor, GF109203X. Both PMA- and NEM-induced receptor proteolysis were, however, inhibited by the metalloprotease inhibitor, Immunex Compound 3 (minimum effective concentration, 10 microM). Notably, PMA and NEM also promoted shedding of GHBP into the conditioned medium of the cells, as determined by a chromatographic [125I]human GH binding assay; this GHBP shedding was also inhibited by Immunex Compound 3. These results strongly implicate a member(s) of the metalloprotease family as a potential GHBP-generating enzyme.

Animals↗
PubMed1998

[Verification and epidemiological study on endemic iodide-induced goiter in Jiangsu Old Yellow River flooded plain].

To verify the existence and reveal the epidemiological characteristics of endemic iodide-induced goiter in Jiangsu Old Yellow River flooded plain, 12 spots were selected in this survey. The results showed that the total goiter rate of 22.18% by palpation and 12.83% by B-ultrasound which surpassed the 5%-cutpoint-recommended jointly by WHO/UNICEF/ICCIDD. The urinary iodine median was 962 micrograms/L in 607 samples. The average 24 hours I31iodine-emissivity ratio was 4.6 +/- 0.3% with most of the serum TSH, T4, T3 within normal ranges. Of 1049 water samples in 65 towns, 771 had iodine content over 300 micrograms/L with water iodine concentration over 300 micrograms/L in 52 towns. These findings suggested that goiter in this plain had been endemic which related to excessive iodine in shallow well water. Heavy load of iodine over general population was noticed.

Child↗
PubMed1998

[Studies on biological monitoring of adrenocortical function in workers exposed to carbon disulfide].

OBJECTIVE: To study the effects of carbon disulfide on adrenocortical function and analyze and compare the various biological materials used in biological monitoring by observing the changes of adrenocortical hormones and their metabolites in blood, saliva and urine of a viscose rayon mill exposed to carbon disulfide for long-term. METHODS: Cortisol in blood and saliva was determined by 125I-radioimmunoassay (RIA), cortisol and cortisone in urine by high performance liquid chromatogaphy (HPLC), and their metabolite 17-ketosteroid by chemical method. Data collected were analyzed by SPSS software in microcomputer to compare their difference between two groups, relationship between them and concentrations of carbon disulfide, and consistence between nontraumatic indices in saliva and urine and blood hormone. RESULTS: Levels of adrenocortical hormones and their metabolites in blood, urine and saliva decreased in the workers exposed to concentrations of carbon disulfide exceeding the national allowable standard, and correlated closely with them. There was a good correlationship between indices in blood and in urine. CONCLUSION: Blood cortisol, urine free cortisol, cortisone and its metabolite 17-ketosteroid all are good indices for biological effects reflecting adrenocortical function, and detection for urine cortisol and its metabolite is more practicable because of its non-traumatic features.

17-Ketosteroids↗
PubMed1998

[Techniques in fetal rabbit surgery].

OBJECTIVE: Experimental fetal surgery has been a popular way to study growth and development and wound healing. The rabbit continues to be a reasonable animal model. The key to success of the experiment lies in keeping the survival rate of the operated animal above 80 percent. In this paper a simple experimental method for fetus surgery in rabbits is described. METHODS: Intravenous thiopental sodium is used for general anesthesia. Surgery is performed inside the uterus through hysterotomy or with the caudal part of the fetus out of the uterus. Amniotic fluid is restituted by instillation of warm saline at 37 degrees C. Special care is taken to suture the amnion. RESULTS: Using these techniques carefully, we have had 90 percent of success in fetal surgery experiment. CONCLUSION: A technically simple procedure has been developed for fetal rabbit surgery.

Animals↗
PubMed1998

[Study on the effects of hyaluronic acid-streptomycin perfusion through the round window on the function and morphology in guinea pig inner ears].

To investigate the effects of the hyaluronic acid-streptomycin (HA-SM) perfusion through round window on the function and morphology of the inner ear in guinea pig, membrous labyrinth mapping, temporal bone section after celloidin embedding, transmission electron microscopy, electrocochlegraphy (ECochG) and electronystagmography (ENG) were examined. The nystagmus duration induced by caloric test was obviously reduced in comparison with that of the preoperation (P< 0.01), while the action potential(AP) by ECochG was not obviously changed. The sensory cells of estibular organs were severely damaged, while the morphology of corti's organs were significantly damaged after HA-SM perfusion. The results suggest that the HA-SM perfusion through the round window may selectively destroy the vestibular function, whereas the auditory function is not obviously damaged.

Animals↗
PubMed1998

[Effect of mifepristone on the concentration of epidermal growth factor in serum and villi of early pregnant women].

OBJECTIVE: To investigate the change of epidermal growth factor (EGF) concentration in serum and villi of early pregnant women and its possible effects by mifepristone. METHODS: Twenty normal women as control and sixty-six early pregnant women were enrolled for study. Serum EGF, estradiol (E2) and progesterone (P) concentrations were measured with radioimmunoassay. EGF concentration in villi by surgical aspiration and mifepristone induced abortion were compared. RESULTS: Serum EGF concentration in early pregnant women was significantly higher than that in non-pregnant women (P < 0.01). The serum EGF, E2 and P concentrations increased as pregnancy advanced (P < 0.05). The growth rate of gestational sac declined and serum EGF and P concentrations decreased slightly after administration of mifepristone. Villi EGF content in mifepristone group was significantly lower than that in surgical group (P < 0.05). CONCLUSION: EGF may be involved in regulating embryo development. Mifepristone may interfere embryonic development via inhibiting EGF level.

Abortifacient Agents, Steroidal↗
PubMed1998

[Effect of dietary selenium on the activities of glutathione peroxidase and deiodinase in rat liver].

In order to investigate the effect of dietary selenium on the activities of glutathione peroxidase and deiodinase and the least selenium requirement for their optimal activities, fifty four male weanling Wistar rats of 50-60g body weight were randomly divided into 9 groups and were fed with semisynthetic diets of different selenium level for 20 weeks. The selenium in the diets were 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.1, 0.2 and 5 mg/kg diet respectively. The body weight of ratsin the ninth group was different significantly from the seventh and eighth group, but those in the other eight groups were not significantly different. The activities of liver glutathione peroxidase in 0.1, 0.2 and 5 mg/kg groups were the highest among the nine groups. So at least 0.1 mg/kg diet is required for its normal activity. The activities of the liver type I deiodinase of nine groups were high from 0.05 to 0.2 mg/kg diet groups and at least Se 0.05 mg/kg diet is required for its normal activity.

Animals↗
PubMed1998

[Effects of mifepristone on the serum nitric oxide level and uterine blood flow in early pregnant women].

OBJECTIVE: To study the effects of mifepristone on serum nitric oxide (NO) level and uterine blood flow in early pregnant women. METHODS: Serum NO concentrations of 58 early pregnant women and 15 normal nonpregnant women were measured by a copper-coated cadmium reduction method, and uterine artery and trophoblastic blood flow were determined by color doppler flow imaging (CDFI). The ultrastructure of villi and decidua were studied under electron microscopy. RESULTS: Compared with nonpregnant women, serum NO concentration was significantly higher in early pregnant women(P < 0.01). After administration of mifepristone, serum NO level was significantly decreased, resistance index(RI) and systolic to diastolic ratio(S/D) ratio of uterine artery and trophoblastic blood flow were significantly higher than that of normal early pregnancy(P < 0.05). CONCLUSION: Mifepristone may exert effects on uterine blood flow by decreasing serum NO level.

Abortifacient Agents, Steroidal↗
PubMed1998

[The relationship between epidermal growth factor and its receptor and fetal birth weight].

OBJECTIVE: To investigate the relationship of epidermal growth factor (EGF) and its receptor (EGFR) with fetal birth weight. METHODS: Using enzyme linked immunoabsorbent assay (ELISA) method the EGF concentrations of materal sera, cord blood sera and amniotic fluids were determined in 40 cases with IUGR, 40 cases with term normal birth weight, 25 cases with fetal macrosomias and 15 cases with normal non-pregnant women. Simultaneously using the immunohistochemical method EGFR in placentas and fetal membrance was determined in all groups of pregnancy. RESULTS: The EGF levels in normal non-pregnant women were lower than that in all groups of pregnancy. The EGF concentrations of materal sera, cord blood sera and amniotic fluid in IUGR group were lower than that in normal birth weight group. EGF levels were no difference between fetal macrosomias group and normal birth weight group. There is a positive correlation between the fetal birth weight and EGF concentrations in maternal sera, cord blood sera and amniotic fluids. In IUGR group the number of EGFR in placent and fetal membrane was less than that in normal birth weight group. In macrosomia group placental EGFR number was more than that in normal birth weight group. CONCLUSIONS: EGF and its receptor levels are related with IUGR, EGF concentrations in maternal sera and amniotic fluids in the third trimester may be a valuable index for assessing the fetal growth.

Adult↗
PubMed1998

[Effect of calcitonin gone-related peptide on coronary thrombosis and thrombolytic therapy].

OBJECTIVE: To inverstigate the effect of Caleitonin gene-related peptide (CGRP) on intracoronary thrombosis, thrombolysis, and reocclusion. METHODS: Thirty-six dogs were divided into three groups: saline solution (NS) group, nitroglycerin(NTG) group and CGRP group. The canine model of intracoronary thrombsis was established. Urokinase(UK) was administered intravenously. The time and rate of intracoronary thrombosis, patency and reocclusion were observed. RESULTS: The time of thrombus formation was markedly prolonged in the CGRP group. (NS 41 +/- 9 min, CGRP 72 +/- 11 min P < 0.01). The time of patency was shorted from 80 +/- 7 min(NS), 70 +/- 11 min(NTG) to 50 +/- 9 min(CGRP) (P < 0.01). The time of reocclusion was increased from 20 +/- 10 min(NS), 39 +/- 7 min(NTG) to 65 +/- 12 min(CGRP)(P < 0.01). CONCLUSIONS: CGRP can delay the intracoronary thrombus formation, assist thrombolysis and decrease the reocclusis after thrombolysis.

Animals↗
PubMed1998

[Molecular cloning and DNA sequencing of OspC gene of two strains Borrelia burgdorferi isolated in China].

OBJECTIVE: To investigate the variation of OspC gene in two Chinese isolates of Borrelia burgdorferi. METHODS: PCR technique was used to amplify the OspC gene from the whole cellular DNA of isolates BT01 and BJ-9011. The amplified products were inserted into plasmid pGEM-3ZF(+) and sequenced. RESULTS: Except the signal peptide, the OspC genes of the two isolates BT01 and BJ-9011 were 579 bp and 576 bp which encode 193, 192 amino acids respectively. The nucleotide and amino acids sequence identity between the two strains was 86% and 83%. High homology exists between these Chinese isolates and several foreign isolates (PBi, PKo, B31), especially in BJ-9011. It had 99% nucleotide and amino acid sequence identified with B31. CONCLUSION: Variations in OspC genes are noted between the two Chinese Borrelia burgdorferi isolates and foreign isolates.

Antigens, Bacterial↗
PubMed1998

Pregnancy outcome of patients conceiving within one year after chemotherapy for gestational trophoblastic tumor: a clinical report of 22 cases.

OBJECTIVE: To determine the risk of pregnancy for patients who conceive within one year after successful chemotherapy for gestational trophoblastic tumor (GTT). METHODS: We followed up and analysed retrospectively 22 patients who conceived within one year after receiving chemotherapy for GTT from 1966 through 1996. RESULTS: Of 22 patients, 9 had term delivery, 1 had premature birth, 6 requested induced abortion, and 6 experienced therapeutic abortion because of repeated hydatidiform mole (1 patient), intrauterine death (1), inevitable abortion (1), or threatened abortion (3). The fetal wastage rate was 27.3% (6/22). The incidence of gestational trophoblastic disease (GTD), including hydatidiform mole, was 9.1% (2/22). The incidence of GTT was 4.5%. The average interval between completion of chemotherapy and pregnancy was 9.78 months in the group of term pregnancy and 6.50 months in the group of fetal wastage (P < 0.05). CONCLUSIONS: Patients conceiving within one year after successful chemotherapy for GTT are at higher risk for recurrence of GTD and fetal wastage. Therefore, patients with preserved fertility should practice contraception for at least one year after chemotherapy to get better pregnancy outcome.

Abortion, Threatened↗
PubMed1998

Lipoprotein (a) concentration and apolipoprotein (a) phenotype in subjects with type 2 diabetes mellitus.

OBJECTIVE: To investigate the apolipoprotein (a) [apo(a)] polymorphism in the patients with type 2 diabetes mellitus and its relationship with complications. METHODS: In this study, we tested apo(a) phenotype via modified Utermann and Guo method in the 40 non-diabetic controls and 176 subjects with type 2 diabetes and analyzed the relationship between apo(a) phenotypes and micro- and macrovascular complications, including nephropathy, neuropathy, retinopathy, hypertension, coronary heart disease and cerebral infarction. RESULTS: Among the 40 non-diabetic controls, the frequencies of S3S2, S4 and S4S2 were 20%, 70% and 10% respectively and the serum lipoprotein (a) [Lp(a)] level was 0.08 +/- 0.07 mg/L. While the frequencies of S2, S3, S3S2, S4, S4S2, S4S3 were 18.18%, 20.45%, 17.05%, 34.09%, 4.55% and 5.68% in the diabetics and the Lp(a) concentration was 0.13 +/- 0.11 mg/L, with significant difference between the diabetics and non-diabetic controls. In comparison with the diabetics without complications, the frequency of apo(a) phenotype significantly differed in patients with nephropathy, nephropathy, hypertension, coronary heart disease and cerebral infarction except for diabetic retinopathy. In comparison with patients with S2 phenotype, the levels of fasting plasma glucose (FPG), 2-hour postprandial plasma glucose (2hPG) and glycated hemoglobin A1c (HbA1c) were lower in patients with S4 phenotype. The concentration of Lp(a) and urine albumin index (Alb/Cr) were significantly different among diabetics with different apo(a) phenotype, the highest being in patients with S2, secondly S3, and the lowest S4. CONCLUSION: There were significant differences in the frequency of apo(a) phenotype between subjects with type 2 diabetes and non-diabetic controls, and also in diabetics with or without microvascular and macrovascular diseases. The underlying linkage might be microalbuminuria and insulin resistance.

Adult↗
PubMed1998

[The study on the anti-tumor function of lysozyme in the regional lymph nodes of laryngocarcinoma patients].

The purpose of this study was to discuss the anti-tumor function of lysozyme (LZM) to laryngocarcinoma. The LZM distribution of regional lymph nodes incised from laryngocarcinoma patients in paraffin sections was observed by immunohistochemical technique. By the cell culture technique, autologus laryngocarcinoma cells were used as target cells to evaluate the tumoridical activity of MØ which were isolated from the regional lymph nodes of laryngocarcinoma patients. At the same time, ConA was added as control group. The supernatant of cell culture was collected after 24 hours to detect LZM content. The results indicated that the number of LPM in non-metastatic lymph nodes was significantly more than in metastatic lymph nodes (P < 0.01). The MØ isolated from patients' regional lymph nodes released LZM content and it's tumoridical activity to autologus tumor cells were significantly increased after adding ConA (P < 0.01). The LZM releasing content and tumoridical activity of MØ in non-metastatic lymph nodes were much more than metastatic lymph nodes (P < 0.05). The LZM content and tumoridical activity of MØ were analyzed with linearity relapsing statistics, it was positive linearity relation (r = 0.94, P < 0.01). All above suggests that the LZM of laryngocarcinoma patients is closely related to the anti-tumor function, it improves the tumoridical activity of MØ to autologus laryngocarcinoma cells and accelerates the death of laryngocarcinoma cells.

Adult↗
PubMed1998

[The effect of cytokines on the activation of T cells induced by B7-1-transfected leukemia cells].

OBJECTIVE: To observe the effects of IL-12, IFN-gamma, IL-10 on the B7-1 expression of B7-1 transfected leukemia cells (K562 and HL-60) and on the IL-2 and IFN-gamma expression and production in the peripheral blood mononuclear cells(PBMC) induced by B7-1 transfected K562 and HL-60 cells. METHODS: RT-PCR and ELISA techniques were used to assay the expression and production of IFN-gamma and IL-2. RESULTS: IFN-gamma and IL-12 increased the expressions of B7-1, IL-2 and IFN-gamma, but IL-10 inhibited all the expressions. CONCLUSION: IFN-gamma, IL-10 and IL-12 affected the expression and production of IFN-gamma and IL-2 possibly by affecting the B7-1 expression.

B7-1 Antigen↗