Biomedical subjects

Yuping Wang

Publications and source records attributed to Yuping Wang.

47 records · Page 3Linked to original sources

PubMed2002

Event-related potentials evoked by multi-feature conflict under different attentive conditions.

Event-related potentials (ERPs) were recorded in subjects while they were performing a matching task. The focus of the present study was on the contributions made by ERP recording to revealing the time-course of multi-conflict information processing in the brain during visual attention. Participants were instructed to discriminate whether the attributes of the first stimulus (S1) were the same as those of the second one (S2) of a pair. Stimuli were defined by three features: color, global shape, and local shape. In condition 1, all attributes of the two stimuli of the pair were constant (no conflict); in condition 2, S2 was different from S1 in all attributes (conflict). The experiment comprised three tasks. In task 1, subjects attended to the color of the stimuli and ignored the other attributes. In task 2, they were asked to attend to both color and global shape of stimuli and disregard the local shape. In task 3, all attributes were attended to. An ERP component N270 was elicited by attending to the color conflict in session one. In task 2, attending to color and global shape induced two ERP effects in the conflict condition: N270 and N400. The results suggest that the attended different conflicts of the two visual attributes of the stimuli were processed in series. However, in task 3, only one apparent negative component, N270, was observed in the conflict condition. The difference between data from task 2 and 3 showed that more than one processing model exists in the human brain for processing multiple visual attribute conflicts.

Adult↗

PubMed2002

The N270 component of the event-related potential reflects supramodal conflict processing in humans.

It is unclear whether crossmodal information conflict can initiate the conflict processing system indexed by a component of the event-related potential (ERP) called the N270, which previously has been observed only for visual conflict. ERPs were recorded in ten subjects, while they were engaged in a visual-auditory discrimination task. A visual stimulus of a facial photograph was followed by an auditory stimulus of Chinese syllable [a] or [i], which might be sounded by the same gender of its preceding photograph (gender match) or by different gender (gender conflict). Subjects pressed a button for gender match and another for gender conflict. A prominent N270, similar to that evoked by visual conflicts, was elicited by the auditory stimuli in gender conflict condition. It is likely that N270 reflects the brain activity of a supra-modal conflict processing system.

Acoustic Stimulation↗

PubMed2002

Event-related potentials elicited by stimulus spatial discrepancy in humans.

Sixteen subjects were instructed to discriminate whether the spatial locations of two visual stimuli presented in sequence were identical and event-related potentials (ERPs) were recorded from their scalps. The first and the second stimuli were presented in the same location in condition 1, but were in different locations in condition 2. ERP components of P100, N150, late positive component (LPC) and slow negative wave (SNW) were recorded in condition 1; in condition 2, N150 was enhanced and N270 was elicited before LPC. N150, N270 and SNW were all mainly distributed bilaterally over P3, P4, Pz, O1, O2, and Oz. N270 represents the brain activity for processing spatial discrepancy. There are several specialized brain areas involved in the generation of the N270.

Adult↗

PubMed2002

Early detection of cognitive impairment in patients with obstructive sleep apnea syndrome: an event-related potential study.

Event-related potentials (ERPs) were recorded to visual stimuli in a task that required matching the shape and serial position of the probes against previously memorized items. The effects of hypoxia on ERP were investigated in 24 patients with obstructive sleep apnea syndrome (OSAS) and a matched control group. N2b-late positive-going (LPC) components were elicited by probes that identically matched the memorized items (no-conflict condition). In contrast, N270-LPC and N270-N430-LPC components were elicited by probes having low-conflict and high-conflict with the memory set. Conflict ERP effect decreased in mild, while both no-conflict and conflict ERP effects decreased in amplitude in severe OSAS patients. Conflict ERPs associated with processing of conflicting information are more vulnerable than no-conflict ERPs to hypoxic cerebral damage.

Adult↗

PubMed2002

Endothelial junctional protein redistribution and increased monolayer permeability in human umbilical vein endothelial cells isolated during preeclampsia.

OBJECTIVE: To examine monolayer permeability and junctional protein distribution and expression in endothelial cells isolated from women with preeclampsia and from women with normal pregnancies. We hypothesized that increased endothelial monolayer permeability in preeclampsia reflects altered monolayer barrier properties produced by disorganization of endothelial cell junction proteins. STUDY DESIGN: Endothelial cells were isolated from umbilical veins from women with normal pregnancies (n = 9) and from women with preeclampsia (n = 9) immediately after delivery. In the first passage of endothelial cells, the permeability was determined by measurement of horseradish peroxidase passage through confluent cell monolayers grown on transwell filters, and the distribution and protein expression of vascular endothelial cadherin and occludin were evaluated by use of immunofluorescent staining of the proteins and Western blot analysis. The distribution of vascular endothelial cadherin was also evaluated in the second and third passage endothelial cells. Messenger ribonucleic acid expression of vascular endothelial cadherin and occludin were examined by reverse transcriptase polymerase chain reaction. Data were expressed as mean values (+/- SE) and were analyzed by use of an unpaired t test. RESULTS: The relative monolayer permeability was significantly increased in the endothelial cells isolated from women with preeclampsia compared with those isolated from women with normal pregnancies (0.271 +/- 0.049 versus 0.086 +/- 0.031 for DeltaOD(470); P <.05). Vascular endothelial cadherin expression for normal endothelial cells showed a continuous staining of the junctional protein that surrounded cell borders. In comparison, vascular endothelial cadherin in endothelial cells from preeclamptic pregnancies exhibited disorganized staining and vascular endothelial cadherin fibrils were retracted, with gaps present at the cell borders. The expression of occludin showed a pattern similar to that of vascular endothelial cadherin in both normal and preeclamptic conditions. Western blot results for expression of vascular endothelial cadherin and occludin also showed decreased expression of junctional proteins. The altered endothelial cell junctional protein distribution and expression of vascular endothelial cadherin and occludin observed in the first passage of endothelial cells from preeclamptic pregnancies was restored to normal by the time cells reached the third passage in vitro. There was no statistical difference in mRNA expression for the vascular endothelial cadherin and occludin between normal endothelial cells and those from preeclamptic pregnancies. CONCLUSION: In preeclampsia, increased endothelial cell monolayer permeability appears to reflect disorganized and diminished expression of endothelial cell junctional proteins. The latter response is mediated at the posttranscriptional level. These findings provide new insights about the cellular and molecular basis for altered endothelial cell integrity and barrier dysfunction that are associated with preeclampsia.

Antigens, CD↗

PubMed2002

Effects of nicotine on intercellular adhesion molecule expression in endothelial cells and integrin expression in neutrophils in vitro.

OBJECTIVE: We previously reported that nicotine decreases leukocyte adhesion to uterine vascular endothelial cells in vivo under ischemic conditions in pregnant rabbits. To further investigate the mechanism of decreased leukocyte-endothelial adhesion by nicotine exposure, the effect of nicotine on endothelial cell intercellular adhesion molecule expression and neutrophil integrin expression of CD62L, CD11a, and CD11b were examined. STUDY DESIGN: Endothelial cells were isolated from human umbilical cord veins from normal pregnancies in nonsmoking women immediately after delivery. Neutrophils were isolated from healthy nonpregnant and nonsmoking female volunteers. First passage of endothelial cells and fresh isolated neutrophils were exposed to nicotine at different concentrations. Surface adhesion molecule expression of intercellular adhesion molecule on endothelial cells was determined by colorimetric assay. Neutrophil integrin expressions for CD62L, CD11a, and CD11b were determined by flow cytometry. Messenger RNA expression for intercellular adhesion molecule in endothelial cells was examined by reverse transcription-polymerase chain reaction. RESULTS: Nicotine at a lower concentration of 0.01 micromol/L had no effect on endothelial cell surface intercellular adhesion molecule expression compared with controls (P =.614). Nicotine at a higher concentration of 10 micromol/L completely inhibited endothelial cell surface intercellular adhesion molecule-1 expression(P <.0001). At concentrations between 0.10 and 10 micromol/L, nicotine inhibited intercellular adhesion molecule expression in a dose-dependent manner. Messenger RNA expression of intercellular adhesion molecule in endothelial cells was not changed after exposure to nicotine. Decreased integrin expressions of CD62L, CD11a, and CD11b were observed on neutrophils after exposure to nicotine. CONCLUSION: Nicotine exerts inhibitory effects on both endothelial cell surface intercellular adhesion molecule expression and neutrophil integrin expressions of CD62L, CD11a, and CD11b in vitro. These in vitro effects of nicotine may relate to the clinical observation of reduced incidence of preeclampsia in women that smoke.

Cell Adhesion Molecules↗

PubMed2002

Event-related potentials in a No-go task involving response-tendency conflict.

Event-related potentials (ERPs) were recorded while 13 subjects completed a color discrimination task. In task one, subjects were asked to press a button when the presented stimulus was a red or a green spot (Go stimulus), and inhibited any motor response when the stimulus was a yellow or a white spot (No-go stimulus). In task two, subjects were instructed to count the number of the Go stimuli, not to count the No-go stimuli. In order to investigate the influence of probability on ERP components, two sessions were designed in each task. In session one, the probability of the four kinds of stimuli was equal. In session two, the probability of red, green, yellow, and white were 10%, 10%, 10%, and 70% respectively. An enhanced negative potential in the frontal area was recorded in the 200-400 ms range both following No-go stimuli and following No-count stimuli, which was not influenced by the stimulus probability. The result cast doubt on the interpretation of the frontal negative potential enhancement as reflecting response-inhibition processes. The potential might be related to the information processing of response-tendency conflict rather than the suppression of motor execution.

Adult↗

PubMed2002

Expression of thrombin receptors in endothelial cells and neutrophils from normal and preeclamptic pregnancies.

Thrombin receptors, i.e. proteinase-activated receptors (PARs), are expressed in endothelial cells (ECs) and neutrophils and directly affect platelet function and thrombosis. Although endothelial dysfunction and neutrophil activation have been demonstrated in women with preeclampsia (PE), the expression and regulation of PARs have not been defined in PE. In this study, we measured the expression of PARs in ECs and in neutrophils derived from normal and preeclamptic pregnancies. We also examined the effects of placental factors on PAR expression in these cells in vitro. ECs were isolated from umbilical cords (human umbilical vein ECs) from normal and preeclamptic pregnancies. Neutrophils were isolated from blood obtained from nonpregnant, uncomplicated pregnant, and preeclamptic women. Total RNA was extracted from the first-passage (P1) ECs (normal and PE) and from normal P1 ECs incubated with conditioned media derived from normal and preeclamptic placental cultures. The mRNA expression of thrombin receptor (PAR1), PAR2, and PAR3 was measured by ribonuclease protective assay. The expression of glyceraldehyde 3-phosphate dehydrogenase was used as an internal control for each sample. We found that: 1) PAR1 expression was enhanced in ECs from PE, compared with ECs from normal pregnancies; 2) PAR2 expression was expressed in PE ECs but not in normal ECs; 3) neutrophils from nonpregnant women, normal, and preeclamptic pregnancies expressed PAR2, whereas only neutrophils from normal and preeclamptic pregnancies expressed PAR1; and 4) factors released from preeclamptic placenta up-regulated PAR1 and PAR2 expression in ECs but not in neutrophils. We conclude that mRNA expression of PAR1 and PAR2 is increased in ECs derived from preeclamptic pregnancies. Up-regulation of thrombin receptor expression in neutrophils may be a unique phenomenon during pregnancy but not apparently unique to PE. Factors released from the placenta are likely candidates in regulating PAR expression in ECs and may contribute to the platelet activation and vascular endothelial dysfunction in PE.

Cells, Cultured↗

PubMed2002

Significance of HER-2/neu expression in ovarian epithelial tumours.

OBJECTIVE: To investigate expression of Her-2/neu (c-erbB-2) and its significance in ovarian epithelial tumors. METHODS: 106 specimens and clinical history of ovarian epithelial tumors were collected including 54 cases of malignant, 33 cases of borderline and 19 benign cases. There were 19 cases of stages I and II and 35 cases of stages III and IV in ovarian carcinoma and all borderline malignant cases were stage I according to FIGO's standard. Immunohistochemical staining for Her-2/neu was performed by LSAB method. RESULTS: The positives rates of Her-2/neu of benign, borderline and malignant tumors were 47.4% (9/19), 84.8% (28/33,), and 85.2% (46/54), respectively. Both borderline and malignant cases were found to have higher expression of Her-2/neu than those of benign cases (P < 0.02 and P < 0.01) respectively. Overexpression of Her-2/neu showed in 14/54 (25.9%) of malignant cases, 3/33 (9.1%) of borderline, and none of benign cases. Overexpression of Her-2/neu in malignant tumors cases with metastasis was higher than those without metastasis (P < 0.001). CONCLUSION: Overexpression of Her-2/neu is associated with biological aggressiveness of ovarian cancer.

Female↗

PubMed2002

[Relationship between the heterotopic neurons and intractable epilepsy].

OBJECTIVE: To discuss the relationship between heterotopic neurons and intractable epilepsy. METHODS: Epileptogenic zones were precisely located with MRI, video-EEG monitoring, intracranial electrical recording and electrocorticography monitoring and then resected in seven patients. The removed tissue was processed for conventional pathological examination with immunohistochemical staining. RESULTS: Heterotopic neurons were found in the white matter of the specimens. All the seven cases experienced a favorable outcome, with six seizure free. CONCLUSION: The heterotopic neurons scattered or clustered in the white matter contribute to the pathogenesis of intractable epilepsy.

Adolescent↗

PubMedDate not supplied

The effects of different hands' responses on main ERP components.

The authors recorded event-related potentials (ERPs) in 14 subjects to explore the effects of different hands'responses on ERP components. Subjects used two different fingers of one hand to indicate whether the two sequentially presented visual stimuli were of the same color (match) or not (conflict) in the first half of the test, while they used the other hand in the last half. ERP components of contingent negative variation (CNV), P100, N160, N200, and late positive component (LPC) were recorded in either the match or conflict condition. Component N270 was recorded only in the conflict condition mainly on the centrofrontal area (F3, F4). The mean amplitude of the CNV was significantly higher when subjects used the right hand to respond. The mean amplitudes of N160 in the two conditions and N200 in the conflict condition were significantly higher when the left hand was used to indicate a response. There was no significant difference in the amplitude of N270 between the left-hand and right-hand responses. The N270 is thought to reflect activity in a conflict processing system. The LPC component was not affected by different hands'response-effect.

Adult↗