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Biomedical subjects

X Wu

Publications and source records attributed to X Wu.

At least 595 records · Page 33Linked to original sources
PubMed1998

ERPs of characters of Chinese words compared with tone and picture stimuli in adolescents and aged persons.

ERPs to target stimulation with tone, picture and characters of Chinese words ([symbol: see text] CCW were target stimulus) were studied in adolescents group and aged persons group. The age of the adolescent group ranged from 15-17 years, with 30 males and 30 females; the age of the elderly persons group ranged from 60-79 years with 29 males and 18 females. The latencies of N2 of aged persons in tone stimulus and in picture stimulus among males were longer than those of adolescents. The latencies of P3 and RT of aged persons were longer than those of adolescents in three stimulus models. The gender differences of latencies of N2 and RT were not obvious in two groups, but were apparent in P3 in adolescents. The latencies of N2, P3 and RT of CCW stimulus were longer compared to those of picture stimulus in the adolescent group, but not in the aged persons group.

Adolescent↗
PubMed1998

Two distinct mechanisms for differential positioning of gene expression borders involving the Drosophila gap protein giant.

We have combined genetic experiments and a targeted misexpression approach to examine the role of the gap gene giant (gt) in patterning anterior regions of the Drosophila embryo. Our results suggest that gt functions in the repression of three target genes, the gap genes Krüppel (Kr) and hunchback (hb), and the pair-rule gene even-skipped (eve). The anterior border of Kr, which lies 4-5 nucleus diameters posterior to nuclei that express gt mRNA, is set by a threshold repression mechanism involving very low levels of gt protein. In contrast, gt activity is required, but not sufficient for formation of the anterior border of eve stripe 2, which lies adjacent to nuclei that express gt mRNA. We propose that gt's role in forming this border is to potentiate repressive interaction(s) mediated by other factor(s) that are also localized to anterior regions of the early embryo. Finally, gt is required for repression of zygotic hb expression in more anterior regions of the embryo. The differential responses of these target genes to gt repression are critical for the correct positioning and maintenance of segmentation stripes, and normal anterior development.

Amino Acid Sequence↗
PubMed1998

Enantioselective N-acetylation of N-desisopropylpropranolol by rat liver acetyltransferase.

The enantioselective N-acetylation of N-desisopropylpropranolol (NDP), one of the main metabolites of propranolol (PL), by rat liver acetyltransferase (AT), was investigated. R(+)-NDP or S(-)-NDP was used as a substrate at concentrations ranging from 10 to 200 microM. The cytosol fraction of a rat liver containing 3.93 mg protein/ml served as the source of AT. For 1-amino-3-(1-naphthyloxy)-2-propanol (AcNDP) formation from R(+)-NDP or S(-)-NDP in the presence of infinite AcCoA (250 microM), the Km value was calculated to be 67.5 or 62.4 microM, and the Vmax value was 0.462 or 0.205 nmol/min/mg protein. Based on these findings, the enantioselective N-acetylation of NDP was proved, i.e., AcNDP formation from R(+)-NDP was found to take place more easily than that from S(-)-NDP. Furthermore, AcNDP formation from NDP was competitively inhibited by the exogenous arylamine, p-aminobenzoic acid (PABA), which is well-known to be a typical substrate of AT. The presence of enantioselective inhibition for AcNDP formation was thus confirmed based on the Ki values, 440 microM in the case of R(+)-NDP and 250 microM in the case of S(-)-NDP, respectively, i.e. two-fold enantioselective inhibition was demonstrated based on the Ki values in S(-)-enantiomer in comparison with R(+)-enantiomer.

4-Aminobenzoic Acid↗
PubMed1998

Participation of P450-dependent oxidation of isoniazid in isonicotinic acid formation in rat liver.

By determining the formation amount of isonicotinic acid (INA) from isonicotinic acid hydrazide (isoniazid:INH) in isolated rat hepatocytes, we were able to identify the involvement of the oxidative cleavage of the acid hydrazide. INA formation from INH increased significantly using the isolated hepatocytes prepared from rats pretreated with phenobarbital (PB), 3-methylcholanthrene (3MC), dexamethazone (DEX) and rifampicin (RIF), respectively, in comparison to the control group. On the other hand, a remarkable decrease in INA formation from INH was observed by the addition of such P450 inhibitor as metyrapone or cimetidine as well as an amidase inhibitor bis(p-nitrophenyl)phosphate (BNPP) to the isolated hepatocytes prepared from PB-pretreated rats. By further experiments using rat hepatic microsomes, the oxidative pathway of INA formation in INH metabolism was determined to be P450-dependent, since NADPH and oxygen were both essential for the oxidative pathway of INH to INA and the amount of INA formation was also significantly increased by P450 inducers. Regarding acetylisoniazid (AcINH) and isonicotinic acid amide (INAA), however, INA formation by P450 was little observed in the microsomal experiments.

Animals↗
PubMed1998

Hypertension development in Dahl S and R rats on high salt-low potassium diet: calcium, magnesium and sympathetic nervous system.

Dietary combination of high salt with low potassium (HSLK) exacerbates hypertension development in Dahl salt-sensitive (S) rats, and produces a mild degree of hypertension in otherwise salt-resistant (R) rats. Increased blood pressure in both strains is associated with increased urinary excretion of calcium and magnesium. The objective of this study was to determine the effect of blood pressure on body balance of these ions in Dahl rats on HSLK diet. Two groups of S and two groups of R weanlings were all placed on HSLK diet (NaCl=8%, K=0.2%) for eight weeks. One group of each strain was subjected to chemical sympathectomy with 6-hydroxydopamine (6-OHDA) to counteract hypertension development. Urinary norepinephrine was used to determine efficacy of 6-OHDA treatment. Systolic blood pressures of conscious animals were measured daily throughout the study. The last three days on the diet were used to determine total dietary intake and urinary as well as fecal excretion of sodium, calcium and magnesium. At the end of the study, extracellular fluid volume, serum aldosterone and parathyroid hormone were analyzed. Final systolic blood pressures in the 4 groups were as follows: S=235+/-9 mmHg (n=9); R=155+/-3 mmHg (n=8); 6-OHDA S=151+/-6 mm Hg (n=8); 6-OHDA R=117+/-6 mm Hg. Chemical sympathectomy decreased blood pressure in both S and R rats. There was no indication of sodium accumulation in S rats. Associated with reduced parathyroid hormone levels the S strain had significantly less positive balance for calcium than the R strain, primarily due to increased urinary excretion. A less positive balance for magnesium was also observed, due mainly to relatively reduced intestinal absorption of the ion. We conclude that the HSLK diet is associated with inappropriate activation of the sympathetic nervous system and increased arterial pressure in both strains. In addition, since divalent cations may influence blood pressure, we suggest that the observed abnormalities in calcium and magnesium metabolism might independently promote hypertension development in the S strain.

Animals↗
PubMed1998

Transurethral prostate vaporization using an oval electrode in 82 cases of benign prostatic hyperplasia.

OBJECTIVE: To present our initial experience in transurethral vaporization of the prostate (TVP) using an oval electrode for the treatment of benign prostatic hyperplasia (BPH). METHODS: A total of 82 patients underwent TVP procedures with the oval electrode. The newly designed oval-shaped electrode can work with a High Frequency Electrosurgery Unit. Prostate gland tissue was vaporized through an Fr 24 percutaneous nephroscope transurethrally. The operation procedure was similar to transurethral resection of the prostate (TURP) or transurethral laser prostatectomy (TULP). Power setting ranged from 240 W to 320 W. Local vaporization temperature reached 120 degrees C. RESULTS: Urination was recovered in all 82 patients after TVP. Mean post-treatment International Prostate Symptom Score (I-PSS) reduced from 27.10 to 5.05; mean bladder residual urine volume dropped from 147.71 ml to 33.2 ml; and mean urine flow rate (MFR) increased from 4.45 ml/s to 14.57 ml/s (P < 0.01). The initial results of short-term follow-up were excellent. CONCLUSIONS: TVP with the oval electrode is easy to perform and causes less hemorrhage and few complications. It especially benefits elderly and/or critically-ill patients. We believe that TVP with our oval electrode is feasible with low risk.

Aged↗
PubMed1998

[Expression of mRNA for endothelin-1 and its receptors in rat kidney after burn injury].

OBJECTIVE AND METHODS: We studied expression of messenger RNAS for endothelin-1 (ET-1) and its receptor subunits (ETA, ETB) by northern blot hybridization and in situ hybridization in rat kidney following 30% TBSA full thickness burns. RESULTS: Expressions of that ET-1, ETA, and ETB mRNA expression are all evidently increased at 1 hour postburn. ET-1 and ETA reached its maximal mRNA expression at 3 hour postburn. ET-1 mRNA distributed primarily on glomerular endothelial cells and tubular epithelial cells in cortex. ETA mRNA predominantly presented on smooth muscle cells of small arterioles in renal cortex. However, the peak time of ETB mRNA expression is at 6 hour postburn and mainly localized on renal medullary tubular epithelial and collecting duct cells. CONCLUSION: These findings suggest that 1. ET-1 acts principally as a local paracrine/autocrine peptide. 2. Increased ET-1 that activated ETA receptors accentuated expression on vascular smooth muscle cells will result in renal cortex ischemia. 3. Accentuated expression of ETB receptor on tubular epithelial cells may induce renal natriuretic action and reduction of water execretion. 4. Increased ET-1 and its receptors in kidney play an important role in the pathogenesis and development of renal function impairment following severe burn.

Animals↗
PubMed1998

[The dynamic changes and significances of endothelins in early burned rats].

OBJECTIVE: To elucidate the significance of endothelins in visceral injury at the early stage of burn. METHODS: By use of a 30% (III degree) total body surface area (TBSA) burn rat model, we measured the concentration of endothelins in plasma, heart, liver, lung, kidney, and observed the effects of PD145065, a kind of non-selective ETA-ETB receptor antagonist, on visceral impairment. RESULTS: Not only did the endothelin concentration in plasma of burnt rat elevated significantly, showing a peak at 6 hours postburn, but also the endothelin contents in internal organs apparently increased. The changes in endothelin in liver or kidney were negatively correlated with the alteration in renal or hepatic blood flow. Moreover, administration of endothelin receptor antagonist PD145065, without affecting the arterial blood pressure, could revert the decrease of renal or hepatic blood flow to some extent, reduce the water contents of heart, liver, lung, kidney postburn. CONCLUSION: The abnormal changes in endothelins postburn contribute to visceral injury in the early postburn stage in rats.

Animals↗
PubMed1998

[Lipoprotein lipids in polycystic ovarian syndrome: independent associations with androgen excess and insulin resistance].

OBJECTIVE: To investigate the relationship between androgen excess, insulin resistance and altered lipoprotein lipids in polycystic ovarian syndrome (PCOS). METHODS: Both basal and luternizing hormone-releasing hormone (LHRH, 100 micrograms) induced responses of circulating testosterone (T), triglycerides (TG), high-density lipoprotein-cholesterol (HDL-C) and apoprotein A1 (apo A1) were measured in two PCOS groups with similar T levels (LH/FSH > or = 3, Group 1, n = 15, LH/FSH < 3, Group 2, n = 15) and the control (n = 20) of matched body mass index with Group 1. Insulin resistance was assessed by fasting insulin levels. RESULTS: In basal state, the mean TG levels in women of three groups were as follows: Group 2 > Group 1 > control, while HDL-C showed the opposite. After LHRH test, mean T and TG concentrations increased and HDL-C decreased in all PCOS subjects, especially Group 2 whereas the indices remained unchanged in the controls. CONCLUSION: Our data suggest that altered lipid profiles in women with PCOS may result from the independent effects of androgen excess and insulin resistance.

Adult↗
PubMed1998

[Functional states of pituitary-ovary, adrenal and thyroid axes in women with polycystic ovarian syndrome].

OBJECTIVE: To assess the role of the functional states of pituitary-ovary, adrenal and thyroid axes in the pathophysiology of polycystic ovarian syndrome (PCOS). METHODS: The stimulation tests of above-mentioned three endocrine axes by luteinizing hormone releasing hormone (LRH, 100 micrograms), adrenocorticotrophin (ACTH, 250 micrograms) and thyroid releasing hormoune (TRH, 500 micrograms), respectively, were performed in each subjects of two PCOS groups [luteinizing hormone/follicle stimulating hormone (LH/FSH) > or = 3, Group 1, n = 15; LH/FSH < 3, Group 2, n = 15] and the control (n = 20). Endocrine indices of corresponding target glands were evaluated by radioimmunoassay (RIA). RESULTS: After LRH administration, the amplitude of LH responses in three groups were as follows: Group 1 > Group 2 > control while mean testosterone levels were elevated to a similar extent in two PCOS groups and remained unchanged in the control. Following ACTH stimulation, PCOS subjects, especially of Group 2 with obvious insulin resistance, showed higher responses of cortisol, dehydroepiandrosterone sulfate and testosterone as compared with the controls. However, during TRH testing, exaggerated thyroid-stimulating hormone and prolactin responses in two PCOS groups and blunted free thyroxine response at two hour point in Group 1 were observed, as compared with the control. CONCLUSION: It appears that ovarian androgen excess in women with PCOS is mainly LH-dependent in Group 1 and insulin-dependent in Group 2. Enhanced adrenal activity may contribute to both hyperandrogenism and insulin resistance in this syndrome, and subclinical hypothyroidism may exist in affected subjects, especially of Group 1.

Adult↗
PubMed1998

[Association of apoB levels and nutrition of coronary heart disease patients].

Blood lipids and apo B levels were measured on 101 Coronary Heart Disease patients and 100 controls. The results showed that the apo B levels of patients were higher than that of controls. The average values were (877 +/- 129) mg/L and (800 +/- 95) mg/L respectively. It was found that there was close association among body mass index(BMI), ratio of waist circumference to hip circumference(WHR) and apo B levels. Besides, the results showed that dietary habit of "eating fat meat" might result in the increase of apo B concentration while the VC intake was negatively associated with serum apo B levels.

Adult↗
PubMed1998

[Sjögren's syndrome and malignant lymphoma].

To diagnose and study the early stage of Sjögren's syndrome associated with malignant lymphoma, the authors used the PCR technique of B malignant lymphoma gene for lacrimal gland tissues in four patients with Sjögren's syndrome and in five patients suffering from B malignant lymphoma. The results showed that all cases of Sjögren's syndrome were negative and all cases of B malignant lymphoma were positive. These suggest that in general the patients with primary or secondary Sjögren's syndrome have no malignant lymphoma genes, but those who have chronic fever and enlarged superficial lymph nodes should under go this technique for early diagnosis and treatment of Sjögren's syndrome associated with malignant lymphoma.

Adult↗
PubMed1998

[Proliferating cell nuclear antigen (PCNA) in ovarian carcinoma and its relation to lymph node metastasis and prognosis].

OBJECTIVE: To investigate expression of proliferating cell nuclear antigen (PCNA) in ovarian epithelial cancer and its relation to lymph node metastasis, second-look laparotomy (SLL) and prognosis. METHODS: Monoclonal antibody PC10 was used to stain PCNA in archival paraffin-embedded tissues. RESULTS: PC10 immunostaining was performed successfully in all 74 primary and 31 intraperitoneal metastatic tumors. The expression of PCNA was significantly elevated in 31 metastatic tumors compared with their primary tumor from the same patient (7.94 vs 6.89, P = 0.042). The expression was more marked in bilateral than in unilateral ovarian cancer but it was not associated with lymph node metastasis, clinical stage, histologic grade and subtype. In 28 patients with stage III ovarian cancer undergone SLL, the mean immunoreactive score (IRS) of PCNA of the primary tumor was significantly higher in patients with negative SLL than in those with positive SLL (7.59 vs 6.10, P = 0.03). Since chemotherapy was performed following surgical debulking, negative SLL more frequently seen in patients with high PCNA expression might suggest better chemotherapeutic sensitivity due to higher proliferation fraction of tumor cells. Univariate analysis of survival indicated that the overall survival was inversely associated with the level of PCNA expression, while multivariate analysis with Cox's model showed that independent prognostic factors were the residual tumor after primary debulking (P < 0.001) and clinical stage (P < 0.05), followed by PCNA expression (P = 0.09). CONCLUSION: The expression of PCNA may be useful in predicting prognosis, but is not correlated with lymph node metastasis.

Adult↗
PubMed1998

[Expression of Wilms' tumor gene (WT1) in leukemias and its clinical implication].

OBJECTIVE: To elucidate the expression of Wilms' tumor gene (WT1) in leukemias and its clinical implication. METHODS: Expression of WT1 mRNA was detected in four leukemia cell lines, 25 AML patients, 11 ALL patients, 9 CML patients, 15 healthy subjects and 10 non-blood diseases patients by using RT-PCR. RESULTS: WT1 mRNA expression was revealed in K562, HL-60 and TF-1 cell lines, 21 of 25 (84%) AML patients, 8 of 11 (73%) ALL patients, 2 CML patients in blast crisis and 1 of 7 CML patients in accelerated and chronic phase. WT1 mRNA was undetectable in PBMNC from 15 healthy subjects and in bone marrow cells from 10 non-blood diseases patients. CONCLUSION: WT1 gene is expressed in the majority of acute leukemias and thus is involved in human leukemogenesis. WT1 is also a new important marker for monitoring MRD in acute leukemias.

Adolescent↗
PubMed1998

[Nucleoside diphosphate kinase/nm23H1 expression in ovarian epithelial carcinoma: retroperitoneal lymphatic metastasis and survival].

OBJECTIVE: To determine the relationship between NDPK(A) expression and retroperitoneal lymph node metastasis (LNM) and the significance of the prognosis in epithelial ovarian carcinoma. METHODS: NDPK(A) expression of formalin-fixed parafin-beded samples, which included 74 primary, 31 intraperitoneal and 18 retroperitoneal lymph node metastatic tumors, were examined by ABC immunohistochemisty in 74 patients with primary ovarian cancer. RESULTS: In the 74 primary lesions, 22 samples showed positive staining of NDPK(A) (30%). Positive staining was higher in patients without LNM(46%) than those with LNM (17%, P = 0.008); it was lower in menopausal patients (19%) than in menstruant (44%, P = 0.022). Compared with primary tumor, NDPK(A) expression appeared to decrease in lymph-node lesion(28% vs 39%, P > 0.1) but to increase in intraperitoneal metastastic tumor (32% vs. 19%, P > 0.5). Multivariance analysis confirmed that the important risk factors for LNM were lower expression of NDPK(A), more large residual tumor and poor differentiation. But there was no any corelation between NDPK(A) expression and survia. CONCLUSION: The study suggested that increased expression of NDPK(A)/nm23H1 is inversely related to LNM in epithelial ovarian carcinoma, but it can not confirm the prognostic significance of NDPK(A).

Female↗
PubMed1998

[Effects of protein kinase C on non-heart organ protection of preconditioning].

OBJECTIVE: To investigate the effects of protein kinase C (PKC) on ischemic (hypoxic) preconditioning (PC) in the non-heart organs and tissue. METHODS: In the models of ischemia/reperfusion of in situ perfused rat small intestine, limb, and in the model of hypoxia/reoxygenation of cultured rat aortic vascular smooth muscle cells (VSMC), the effects of PKC on ischemic (hypoxic) PC were observed. RESULTS: PKC inhibitor H7 and polymyxin B completely abolished the protective effects of ischemic PC on small intestine and limb subjected to ischemia/reperfusion injury. Hypoxic PC activated PKC in VSMC and potentiated phosphorylation mediated by PKC. CONCLUSION: The activation of PKC is also the important chain of PC on non-heart organs, and its mechanism might involve protein phosphorylation.

Animals↗