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J H Yang

Publications and source records attributed to J H Yang.

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

[The significance and expression of vascular endothelial growth factor on nasal inverted papillomas].

OBJECTIVE: To determine the expression of vascular endothelial growth factor (VEGF) and its receptor in nasal inverted papillomas (NIP) and to clarify the function of VEGF in the establishment of NIPs. METHOD: VEGF and its receptor, fetal liver kinase-1 (flk-1) expression were examined by immunohistochemistry using SP method in sections of NIPs from 11 patients and inferior turbinates from 6 patients with chronic simple rhinitis. An automatic image analyzer was used to detect the staining results. Gray scale, a half-quantitative parameter, was used to describe the expression of VEGF and flk-1. RESULT: It showed that all the epithelium in NIPs, together with vascular and stroma adjacent to the epithelium, expressed different degree of VEGF. The VEGF expression in epithelium was significantly stronger in NIPs than that in inferior turbinates (P < 0.001). The expressions of both VEGF and flk-1 in vascular endothelium were more intense in NIPs than that in inferior turbinates (P < 0.001, P < 0.001). Flk-1 positive expression was observed in epithelium of NIPs but not in inferior turbinates. CONCLUSION: The results suggest that VEGF participate in the growth of NIPs, part of which shows the characteristics of containing plenty of blood vessels and being bloody in operation. The enhanced expression of VEGF may also play a key role in the development of edematous stroma. The expression degree of VEGF in the epithelium may be identified as one of the parameters of judging the propensity of NIPs' malignant transformation.

Aged↗
PubMed1999

Specificity of DNA binding of the c-Myc/Max and ARNT/ARNT dimers at the CACGTG recognition site.

Basic helix-loop-helix proteins that interact with the DNA recognition site CACGTG include the c-Myc/Max heterodimer and the ARNT (Ahreceptornucleartranslocator) homodimer. We have utilized a PCR-based protocol to identify high affinity binding sites of either the c-Myc/Max or ARNT/ARNT dimers and analyzed the ability of these dimers to interact with their derived consensus sequences and activate genes. chi(2)analysis of the selected DNA recognition sites revealed that DNA binding of the ARNT homodimer is symmetric, resulting in the consensus sequence RTCACGTGAY. Gel shift analysis demonstrated that the flanking nucleotides play an important role in dictating DNA binding affinity of the ARNT homodimer. These flanking sequences also regulate the ability of ARNT to competitively displace the c-Myc/Max heterodimer from a CACGTG-containing sequence. However, transient transfection analyses in CV-1 cells revealed that ARNT and c-Myc/Max exhibited similar abilities to activate transcription through each other's consensus sequences. Taken together, these results indicate that although binding affinity of these dimers for the CACGTG core sequences may be differentially influenced by flanking nucleotides, transcriptional activity may also be determined by other factors, such as cellular concentrations of these proteins and their co-activators.

Aryl Hydrocarbon Receptor Nuclear Translocator↗
PubMed1999

Expression of dioxin-responsive genes in human endometrial cells in culture.

To investigate expression of dioxin-responsive genes in human endometrial cells with exposure to 2,3,7, 8-tetrachlorodibenzo-p-dioxin (TCDD), human endometrial stromal cells immortalized with temperature-sensitive SV40 T antigen were used for the experiments. Cells were treated with 0.1% DMSO or 0.1, 1, 10, or 100 nM TCDD for 24 h. Induction of interleukin-1beta (IL-1beta) and plasminogen activator inhibitor-2 (PAI-2) mRNAs was analyzed by reverse-transcription polymerase chain reaction. Expression of IL-1beta or PAI-2 mRNA in response to TCDD was increased in a dose-dependent fashion. The maximum increases of PAI-2 and IL-1beta mRNAs were observed at 100 and 10 nM TCDD, respectively. While cycloheximide treatment did not show a significant difference of PAI-2 mRNA levels between control and TCDD-treated cells, mRNA stability assay using actinomycin D showed that PAI-2 mRNA in TCDD-treated cells was about twofold more stable than the control cells. While expression of CYP1A1 mRNA was not detected and levels of ARNT mRNA were not altered by TCDD exposure, the amount of AhR mRNA was decreased dose dependently. The present study represents an initial attempt to determine the responses of dioxin-responsive genes in human endometrial cells following TCDD exposure. The results demonstrated that IL-1beta and PAI-2 genes are induced dose dependently in human endometrial cells with exposure to TCDD and expression of PAI-2 mRNA is controlled at the posttranscriptional level.

Aryl Hydrocarbon Receptor Nuclear Translocator↗
PubMed1999

The expression of killer cell inhibitory receptors on natural killer cells and activation status of CD4+ and CD8+ T cells in the decidua of normal and abnormal early pregnancies.

The establishment of the human placenta in early pregnancy is characterized by the presence of large numbers of natural killer cells within the maternal decidua. These NK cells have an unusual phenotype, CD3- CD16- CD56(bright), distinguishing them from peripheral blood NK cells. They may control trophoblast migration and placentation. Using a panel of monoclonal antibodies to several members of the KIR family and flow cytometry, we found that KIRs are expressed on decidual NK cells. There is variation in both the percentage of cells expressing a particular receptor and the density of receptor expression between decidual NK cells from different individuals. In anembryonic pregnancy, the proportions of decidual NK cells with a particular KIRs (GL183 and EB6) decreased significantly when compared with normal pregnancy (p = 0.01 and 0.01, respectively), raising the possibility that these NK receptors may be involved in recognition of the allogeneic fetus by the mother at the implantation site. In the decidua, more CD4+ and CD8+ T cells expressed CD69 and HLA-DR than in blood, indicating that T cells are regionally activated during early pregnancy. When compared with normal pregnancy, decidual HLA-DR+CD4+CD3+, CD69+CD8+CD3+ and HLA-DR+CD8+CD3+ T lymphocytes are significantly increased in anembryonic pregnancy. The over-activation of decidual T cells during anembryonic pregnancy may thus contribute to the increased NK cytotoxicity activity.

Antigens, CD↗
PubMed1999

Tetralogy of Fallot in the fetus: findings at targeted sonography.

OBJECTIVES: To evaluate the findings of tetralogy of Fallot in various fetal sonographic views. METHODS: We reviewed the fetal sonograms and medical records of 20 fetuses with prenatal diagnosis of tetralogy of Fallot. We analyzed the indications for targeted sonography, the abnormalities seen in various sonographic views, the postnatal echocardiographic and angiographic findings and autopsy findings. RESULTS: The most common indication for targeted sonography was an abnormal (n = 12) or inadequate (n = 3) finding on sonographic screening in which the abnormality was most frequently found on the three-vessel view (n = 9). The key pathological features of tetralogy of Fallot were uniformly demonstrated in the ventricular outflow tract, three-vessel and short-axis views. The ductus arteriosus was small in 70% of cases and not identifiable in the remaining fetuses. In three of six fetuses with no identifiable ductus, the ductus was shown to be absent at autopsy. The direction of ductal flow was variable. CONCLUSION: The key features of tetralogy of Fallot were always demonstrable in the ventricular outflow tract, three-vessel and short-axis views. The most common reason for referral was the abnormal three-vessel view.

Female↗
PubMed1999

Detection of RET/PTC oncogene rearrangements in Korean papillary thyroid carcinomas.

The prevalence of RET/PTC rearrangement in papillary thyroid carcinomas has been found to vary widely in different populations. Recent studies, however, have reported no significant geographical difference between Asian and Western countries. In addition, there are some disagreements about the correlation of RET/PTC expression with clinical aggressiveness. We have performed this study in order to examine the prevalence of RET/PTC-1, RET/PTC-2, and RET/PTC-3 rearrangements in Korean papillary thyroid carcinomas, and to ascertain its clinical relevance. Thyroid tumors from 31 patients histologically confirmed to be papillary carcinomas were included in this study. To find rearrangements, we utilized reverse transcription-polymerase chain reaction (RT-PCR) and automated direct sequencing. Initial and follow-up clinical data were obtained from the patients' medical records. We identified two tumors containing RET/PTC-1 (2/31, 6.5%) and two containing RET/PTC-2 (2/31, 6.5%). However, we could not find RET/PTC-3 rearrangement in any patients (0/31). In conclusion, we report RET/PTC rearrangements in 4 of 31, (12.9%) Korean patients with papillary thyroid carcinomas, a higher prevalence than previously reported in this population.

Adult↗
PubMed1999

A malignant transformation of human cells by 2,3,7,8-tetrachlorodibenzo-p-dioxin exhibits altered expressions of growth regulatory factors.

The neoplastic transformation of human cells in culture with exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) has recently been reported. In this study, expressions of growth regulatory factors were analyzed to examine their possible roles in TCDD-induced malignant transformation of human cells. Reverse transcription-polymerase chain reaction (RT-PCR) and immunoblot analysis were performed to detect altered expressions of genes associated with dioxin responses. The RT-PCR analysis showed that expressions of the growth regulatory factors, such as transforming growth factor-beta1 (TGF-beta1), plasminogen activator inhibitor-2 (PAI-2) and tumor necrosis factor-alpha (TNF-alpha), were significantly changed in the transformed cells as compared with the parental cells. Whereas parental cells showed a dose-dependent increase of PAI-2 mRNA levels following TCDD exposure, the transformed cells did not show any significant induction. In addition, constitutive levels of PAI-2 mRNA were 25 times lower in the transformed cells than in the parental cells. The mRNA stability assay suggests that downregulation of PAI-2 mRNA in the transformed cells may be associated with the posttranscriptional control. Expression of TGF-beta1 mRNA in the transformed cells was also four times lower than the parental cells. However, levels of TNF-alpha mRNA in the transformed cells were increased 3-fold. These results suggest that dysregulation of growth regulatory factors may be involved in TCDD-induced cellular transformation. Whereas plenty of studies demonstrated a number of immediate toxic effects by TCDD, this study revealed an initial evidence that altered expression of growth regulatory genes, such as PAI-2, TGF-beta1 or TNF-alpha, are some of the genetic events fixed in the genome following the successive cell divisions of TCDD-damaged cells. It is suggested that these changes may be associated with TCDD-induced malignant transformation of human cells.

Aryl Hydrocarbon Receptor Nuclear Translocator↗
PubMed1999

Association of endometrial blood flow as determined by a modified colour Doppler technique with subsequent outcome of in-vitro fertilization.

An endometrial thickness of 10 mm or more has been reported to be favourable for embryo implantation. Nevertheless, many women participating in in-vitro fertilization (IVF) programmes have adequate endometrial thickness but do not achieve satisfactory implantation. With the aid of power Doppler sonography, we examined the association between intra-endometrial vascularity and reproductive outcome. For this study, we enrolled only women with endometrial thickness >/=ISOdia>/=10 mm and excluded those with apparent endometrial pathologies. Of 95 women undergoing IVF cycles, there resulted 37 intrauterine pregnancies. The women were of similar age, body mass index, peak oestradiol concentration and endometrial thickness, and a similar number of embryos were transferred. Those women with an intra-endometrial power Doppler area (EPDA) <5 mm2 achieved a significantly lower pregnancy rate (23. 5 versus 47.5%, P = 0.021) and implantation rate (8.1 versus 20.2%, P = 0.003) than those with an EPDA >/=ISOdia>/=5 mm2. We conclude that, in addition to endometrial thickness, EPDA may serve as a factor indicative of endometrial receptivity. Women with adequate endometrial thickness but a small EPDA tended to have an unfavourable reproductive outcome.

Adult↗
PubMed1999

Granulomatous mastitis: mammographic and sonographic appearances.

OBJECTIVE: The objective of our study is to describe the mammographic and sonographic appearances of granulomatous mastitis. CONCLUSION: Granulomatous mastitis can mimic breast carcinoma clinically and mammographically, but the sonographic appearance of multiple clustered, often contiguous tubular hypoechoic lesions that are sometimes associated with a large hypoechoic mass should suggest the possibility of granulomatous mastitis.

Adult↗
PubMed1999

Effect of angiopeptin and aspirin on accelerated graft atherosclerosis in transplanted mouse heart.

In this study of the inhibitory effects of angiopeptin and aspirin on the development of accelerated graft atherosclerosis (AGAS), 22 B10.BR mice received intra-abdominal heterotopic heart transplants from B10.A mice, without immunosuppression. Group 1 (n = 5) received no pharmacological intervention, Group 2 (n = 6) was treated with angiopeptin, Group 3 (n = 5) with aspirin, and Group 4 (n = 6) with both. There was no significant difference in the incidence of AGAS among these groups. The magnitude of intimal lesion development showed less narrowing of large vessels (> 100 microns in diameter) in groups 2 and 4--i.e. the groups received angiopeptin (Group 1 = 46.9 +/- 9.3%, Group 2 = 28.5 +/- 9.2%, Group 3 = 44.1 +/- 10.9%, Group 4 = 24.2 +/- 5.9%; p < 0.01). Comparison of the fraction of tropomyosin-positive staining cells in the intima revealed a lesser degree of staining in Group 2 (p < 0.01). No intervention was effective in preventing smooth muscle cell proliferation in the media or inflammatory cell infiltration in the adventitia. In conclusion, our data suggest that angiopeptin is effective in the direct inhibition of intimal smooth muscle cell proliferation in relatively large vessels, whereas aspirin exhibits no inhibitory role in the progression of AGAS. Angiopeptin appears to be a potential therapeutic agent for inhibiting the progression of postoperative AGAS in clinical heart transplantation.

Animals↗
PubMed1999

Benign papillary lesions of the breast: sonographic-pathologic correlation.

We reviewed the sonographic findings of 42 benign papillary lesions of the breast and correlated them with pathologic findings. Sonography detected 95% of papillomas (22 intraluminal masses, four extraductal masses, nine purely solid masses, and five mixed type masses). The sonographic margins of the mass were well defined in 20 lesions and poorly defined in 14 lesions. Poorly defined margins on sonography were frequent in papillomas with pathologic pseudoinvasion and in juvenile papillomatosis. Most benign papillary lesions of the breast have the sonographic findings suggestive of intraductal origin. The sonographic findings of papillary lesions correlated well with pathologic findings.

Adolescent↗
PubMed1999

Urinary follicle stimulating hormone can be used as a biomarker to assess male reproductive function.

AIM: To develop an algorithm for use in population-based studies to assess testicular function by measurements of total urinary follicle stimulating hormone (FSH). METHODS: Total concentrations of urinary FSH were measured in a group of 44 men at the University of California, Davis (UCD) and were compared to FSH measurements in serum. On the basis of these and other published data, a urinary FSH value of >2 ng/mg creatinine (Cr) was selected as the cutoff point to identify men with elevated serum FSH ( > 12 IU/L) or low sperm counts ( < 20 million/mL). RESULTS: The sensitivity and specificity of this algorithm for detecting elevated serum FSH in a group of 58 agricultural workers in the People' s Republic of China were 100% and 50%, respectively. The sensitivity and specificity of this algorithm for detecting low sperm counts in a population of 105 infertility patients at UCD were 58 % and 76 %, respectively. CONCLUSION: This test may have particular value in identifying populations with no evidence of testicular toxicity, and in which labor-intensive semen studies may not be feasible.

Biomarkers↗
PubMed1998

Postsynaptic responses of horizontal cells in the tiger salamander retina are mediated by AMPA-preferring receptors.

The postsynaptic responses of sign-preserving second-order retinal neurons (horizontal cells (HCs) and off-bipolar cells) are mediated by CNQX-sensitive AMPA/KA glutamate receptors. In this study we used receptor-specific allosteric regulators of desensitization and selected antagonists to determine the glutamate receptor subtypes in tiger salamander horizontal cells. Two approaches were employed in this study. The first was to measure postsynaptic currents induced by exogenously applied glutamate under voltage clamp conditions in living retinal slices; and the second was to record voltage responses controlled by endogenous glutamate released from photoreceptors in whole retinas. Application of 100 microM cyclothiazide (a specific AMPA receptor desensitization blocker) enhanced the glutamate-induced current by about 5 fold. In contrast, 300 microgram ml-1 Co nA (a specific kainate receptor desensitization blocker), had no effect. GYKI 52466 (a specific AMPA receptor antagonist) at 30 microM almost completely suppressed the glutamate-induced inward current in HCs. Cyclothiazide at 100 microM depolarized the HC dark membrane potential by about 5 mV and reduced the amplitudes of the voltage responses to dim lights, but enhanced the voltage responses to bright lights. Cyclothiazide had no effect on either the dark potential or the light responses of rods and cones. Con A at 300 microgram ml-1 had no effect on either the dark potential or the light responses of the HC. GYKI 52466 (30 microM) hyperpolarized the HC dark membrane potential by about 55 mV and almost completely suppressed the light responses. We conclude from these results that the postsynaptic glutamate- and light-induced responses in the tiger salamander retinal horizontal cells are mediated by AMPA-preferring, and not kainate-preferring glutamate receptors. The functional roles of AMPA receptors and their desensitization kinetics in visual information processing are discussed.

Ambystoma↗
PubMed1998

Small mechanical strains selectively suppress matrix metalloproteinase-1 expression by human vascular smooth muscle cells.

Mechanical forces and biochemical stimuli may interact to regulate cellular responses. In this study, we tested the hypothesis that very small mechanical strains interact with growth factors in the regulation of matrix metalloproteinase (MMP)-1. Human vascular smooth muscle cells (VSMCs) were cultured on a precoated silicone membrane in a device that imposes a highly uniform biaxial strain. VSMCs cultured on fibronectin were treated with cyclic 1-Hz strains of 0, 1, or 4%, and MMPs were assayed by Western analysis or gelatin zymography. Small strains did not induce MMP-1 in VSMCs, but strain was a potent inhibitor of platelet-derived growth factor (PDGF)- or tumor necrosis factor-alpha-induced synthesis of MMP-1. In contrast, MMP-2 and TIMP-2 levels were not changed by PDGF and/or mechanical strain. VSMCs strained on the 120-kDa chymotryptic fragment of fibronectin or RGD peptides suppressed PDGF-induced expression of MMP-1, indicating that this effect is not mediated by the heparin-binding domain or connecting segment-1 of fibronectin. Northern analysis of ets-1, a transcriptional activator of MMP-1 expression, showed that strain down-regulated ets-1 expression, whereas c-fos expression was augmented. Thus, small deformations can selectively suppress MMP-1 synthesis by VSMCs, demonstrating the exquisite sensitivity of the cell to mechanical stimuli.

Collagenases↗
PubMed1998

Alterations of signal transduction pathways involved in 2,3,7,8-tetrachlorodibenzo-p-dioxin-induced malignant transformation of human cells in culture.

Effects of signal transduction pathways in TCDD-induced neoplastic transformation of human cells were assessed with respect to PLC-coupled signaling pathways, adenylyl cyclase-mediated responses and PKC isozyme expressions. A lower stimulation of the intracellular free calcium levels with exposure to extracellular ATP or histamine was observed in the transformed cells, as compared to the parental cells. While the steady-state level of IP3 was higher in the transformed cells, the magnitude of stimulation of IP3 generation by ATP or histamine was significantly lower in the transformed cells than the parental cells. These results indicate that a downregulation PLC-coupled signaling pathways may be involved in the TCDD-induced transformation of human cells. While the steady-state levels of cAMP accumulation were similar between the two cell lines, treatment of PGE2, a potent differentiation inducer, stimulated a higher accumulation of cAMP in the parental cells but isoproterenol, a typical beta-adrenergic agonist, did not induce a significant difference between the two cell lines. These results suggest that desensitization of cAMP-mediated response to extracellular signals including differentiation signals may be associated with a possible mechanism of the carcinogenesis. Elevated expression of PKC-alpha, -gamma, -zeta, -epsilon, -lambda, and -tau were observed in TCDD-transformed cells, indicating a possible association of altered expression of PKC isozymes with TCDD-induced transformation of human cells. The present study demonstrates that alterations of signal transduction pathways are involved in the TCDD-induced transformation of human cells and provides a valuable basis to investigate effects of signaling pathway as a possible mechanism of TCDD-induced carcinogenesis in human cells.

Blotting, Western↗
PubMed1998

Effects of repeated abdominal paracentesis on uterine and intraovarian haemodynamics and pregnancy outcome in severe ovarian hyperstimulation syndrome.

The aims of this study were to investigate the effects of paracentesis on uterine and intraovarian haemodynamics by colour Doppler ultrasound and the influences of repeated paracentesis on pregnancy outcome in severe ovarian hyperstimulation syndrome (OHSS). Forty-one abdominal paracenteses were performed on seven pregnant women with tense ascites and eight thoracocenteses were performed on three pregnant women with pleural effusion. Pulsatility index (PI) and maximum peak systolic velocity (MPSV) of uterine and intraovarian arteries were measured before and after each intervention. The mean PI of uterine arteries was decreased significantly after paracentesis, but not after thoracocentesis. Furthermore, uterine PI was decreased in 13 out of 14 (92.9%) paracenteses with <2500 ml ascites removed, compared with eight out of 13 (61.5%) with >2500 ml ascites removed. After paracentesis, there were no significant changes in the intraovarian PI and MPSV in either group. The 24-hour urine output increased significantly in the paracentesis group, but not in the thoracocentesis group. There were no significant changes in haematocrit and electrolytes as a result of paracentesis. However, gradual falls in serum total proteins and albumin concentrations were observed in all patients after repeated paracentesis, necessitating post-paracentesis albumin infusion. There was no significant difference in miscarriage rates between the two groups. We conclude that repeated abdominal paracentesis increases uterine perfusion and has no adverse effects on pregnancy outcome in severe OHSS. Extraction of 2500 ml of ascitic fluid did not impair uterine perfusion.

Adult↗
PubMed1998

A case of ischemic colitis associated with pheochromocytoma.

A 40-year-old woman was admitted because of abdominal pain and diarrhea. She sometimes experienced paroxysmal hypertension, sweating, headache, and palpitation. Sigmoidoscopic findings showed well-demarcated diffuse mucosal edema, hyperemia, and easy touch bleeding from distal descending colon up to the splenic flexure area. Barium x-ray showed loss of haustral marking, thumb printing appearance, and diffuse luminal stenosis in the transverse, descending, and sigmoid colon. On the abdominal computed tomogram, a 3.8-cm sized well-enhanced right adrenal mass was incidentally found. Twenty-four hour urinary excretion of vanillyl mandelic acid, norepinephrine, and normetanephrine were increased. Iodine131 metaiodobenzylguanidine scan showed hot uptake on the right adrenal gland compatible with pheochromocytoma. Exploratory laparotomy was done under the impression of ischemic colitis associated with pheochromocytoma. Adrenalectomy and resection of the stenotic left colon were performed. After surgery, pain subsided, blood pressure fell gradually, blood sugar and catecholamine level became normal, and bowel habit returned to normal.

Adrenal Gland Neoplasms↗