Biomedical subjects

Y C Yang

Publications and source records attributed to Y C Yang.

At least 91 records · Page 5Linked to original sources

PubMed1998

Well-differentiated papillary villoglandular adenocarcinoma of the uterine cervix: a case report.

In contrast to other types of cervical adenocarcinoma, well-differentiated papillary villoglandular adenocarcinoma of the uterine cervix is unique for its tendency to develop in young women and its excellent prognosis. Until now, no tumor recurrence has been reported in the English literature following surgical treatment that varies from conization to radical hysterectomy. We report a case of 47-year-old female who presented with postcoital bleeding and was treated by radical hysterectomy for FIGO (International Federation of Gynecologists and Obstetricians) Stage Ib cervical carcinoma, in which the preoperative cervical biopsy diagnosis was adenocarcinoma. The patient was well at follow-up nine months after surgery. A literature review including treatment implications is presented.

Biopsy↗

PubMed1998

High-grade endometrial stromal sarcoma in a 10-year-old girl: case report.

Endometrial stromal sarcomas occur primarily in perimenopausal women and are quite uncommon in children. We report a case of high-grade endometrial stromal sarcoma in a 10-year-old girl, who initially experienced lower abdominal pain on voiding. After a series of examinations, surgical treatment was performed, including an extended total hysterectomy with bilateral salpingo-oophorectomy, bilateral pelvic lymph node sampling, and partial omentectomy. Adjuvant radiotherapy and hormonal therapy followed, however, the abdominal tumor recurred 9 months later. Invasion of the right lobe of the liver with compression of the inferior vena cava and pleural effusion was noted. The patient then received prolonged oral etoposide therapy. The treatment stabilized the tumor size and relieved her symptoms for 4 months. She finally succumbed to the disease as a result of distant metastasis.

Child↗

PubMed1998

Pulsatile ocular blood flow and intraocular pressure during retrobulbar injection of lignocaine: influence of additives.

PURPOSE: To assess the influence of adrenaline and hyaluronidase on pulsatile ocular blood flow and intraocular pressure changes during retrobulbar anesthesia. METHOD: Patients undergoing cataract surgery under local anesthesia received a 5-mL retrobulbar injection of lignocaine with either adrenaline, hyaluronidase, or no addition. Continuous pneumotonometry was performed using the OBF tonograph (OBF Labs, Chippenham, UK), which automatically derives pulsatile ocular blood flow values. Measurements were taken before and one minute after injection, and changes were compared between groups to evaluate the effects of changing the constituents of the injection. RESULTS: There was a marked decrease in pulsatile ocular blood flow during injection in all groups. In the group receiving lignocaine with hyaluronidase, the decrease in pulsatile ocular blood flow (mean -141 microL/min) was significantly less than in either the group receiving lignocaine and adrenaline (mean -249 microL/min) or the group receiving lignocaine alone (mean -245 microL/min). There was no significant change in intraocular pressure in any group. CONCLUSION: Hyaluronidase appears to lessen the reduction in pulsatile ocular blood flow. Injection volumes of 5 mL need not cause significant intraocular pressure change.

Anesthesia, Local↗

PubMed1997

Critical cytoplasmic domains of human interleukin-9 receptor alpha chain in interleukin-9-mediated cell proliferation and signal transduction.

Interleukin-9 receptor (IL-9R) complex consists of a ligand-specific alpha chain and IL-2R gamma chain. In this study, two regions in the cytoplasmic domain of human IL-9Ralpha were found to be important for IL-9-mediated cell growth. A membrane-proximal region that contains the BOX1 consensus sequence is required for IL-9-induced cell proliferation and tyrosine phosphorylation of Janus kinases (JAKs). Deletion of this region or internal deletion of the BOX1 motif abrogated IL-9-induced cell proliferation and signal transduction. However, substitution of the Pro-X-Pro in the BOX1 motif with Ala-X-Ala failed to abolish IL-9-induced cell proliferation but decreased IL-9-mediated tyrosine phosphorylation of JAK kinases, insulin receptor substrate-2, and signal transducer and activator of transcription 3 (STAT3) and expression of c-myc and junB. Another important region is downstream of the BOX1 motif and contains a STAT3 binding motif YLPQ. Deletion of this region significantly impaired IL-9-induced cell growth, activation of JAK kinases, insulin receptor substrate-2, and STAT3 and expression of early response genes. A point mutation changing YLPQ into YLPA greatly reduced IL-9-induced activation of STAT3 and expression of c-myc but did not affect cell proliferation. These results suggest that cooperation or cross-talk of signaling molecules associated with different domains of IL-9Ralpha other than STAT3 is essential for IL-9-mediated cell growth.

Animals↗

PubMed1997

Transcriptional induction of multiple cytokines by human respiratory syncytial virus requires activation of NF-kappa B and is inhibited by sodium salicylate and aspirin.

Infection of the lung epithelial cell line A549 by respiratory syncytial virus (RSV) resulted in the elevated synthesis of multiple cellular cytokines, including a number of interleukins (ILs). Detailed studies of IL-11 induction revealed that it required infection by viable virus and involved a net increase in the steady state level of IL-11 mRNA. Nuclear run-on assays showed a direct effect of RSV on IL-11 gene transcription. Mutational analysis of the IL-11 promoter fused to a reporter luciferase gene demonstrated the requirement of a region 720 nucleotides upstream of the mRNA start site in the transcriptional induction of IL-11 by RSV. Two nearly identical 10-nucleotide-long sequences GGGGTCTCCC and GGGTCTCCCC in this region resembled the NF-kappa B consensus motif. Mutation of either sequence greatly reduced RSV-mediated induction of IL-11 promoter activity. NF-kappa B sites in IL-1 alpha, IL-6, and IL-8 promoters were also required for RSV-mediated induction of transcription of these promoters. Immunological studies and use of reporter gene constructs provided direct evidence for the activation and nuclear translocation of NF-kappa B by RSV. Sodium salicylate and aspirin, inhibitors of NF-kappa B activation, abolished transcriptional induction of all these cytokines by RSV. Together, these studies demonstrated an essential role of NF-kappa B in RSV-mediated transcription of multiple cytokines genes and suggested a possible use of salicylates in managing airway inflammation and viral pathogenesis during RSV infection.

Anti-Inflammatory Agents, Non-Steroidal↗

PubMed1997

Molecular characterization of specific interactions between SHP-2 phosphatase and JAK tyrosine kinases.

Interactions between SHP-2 phosphotyrosine phosphatase and JAK tyrosine kinases have recently been implicated in cytokine signal transduction. However, the molecular basis of these interactions is not well understood. In this study, we demonstrate that SHP-2 is tyrosine-phosphorylated by and associated with JAK1 and JAK2 but not JAK3 in COS-1 cell cotransfection experiments. SHP-2 phosphatase activity appears not to be required for JAK and SHP-2 interactions because SHP-2 with a mutation at amino acid 463 from Cys to Ser, which renders SHP-2 inactive, can still bind JAKs. We further demonstrate that SHP-2 SH2 domains (amino acids 1-209) are not essential for the association of JAKs with SHP-2, and the region between amino acids 232 and 272 in SHP-2 is important for the interactions. Furthermore, tyrosine residues 304 and 327 in SHP-2 are phosphorylated by JAKs, and phosphorylated SHP-2 can associate with the downstream adapter protein Grb2. Finally, deletion of the N terminus but not the kinase-like domain of JAK2 abolishes the association of JAK2 with SHP-2. Taken together, these studies identified novel sequences for SHP-2 and JAK interactions that suggest unique signaling mechanisms mediated by these two molecules.

Animals↗

PubMed1997

Cervical cancer in young women in Taiwan: prognosis is independent of papillomavirus or tumor cell type.

The objective of this study was to address the hypotheses that younger patients with cervical cancer have a uniquely worse clinical outcome and/or are more likely to have adverse tumor cell types or specific human papillomaviruses (HPV). Cases of stage Ib-IIa cervical cancer among women 35 years of age or younger (82) and over 35 (54) were analyzed and compared with respect to the following: (1) histologic type (squamous vs nonsquamous), (2) human papillomavirus (HPV) type via polymerase chain reaction, and (3) clinical parameters, including tumor size, nodal metastases, and recurrence/persistence. Patients 35 years of age or younger had a survival similar (71.2% vs 72.4%) to that of older women from the same institution. In the younger group, outcome was not correlated with the presence or absence of HPV or HPV type. Nonsquamous carcinomas, including adenocarcinoma and small cell carcinoma, were strongly associated with HPV18, were more prevalent in the younger group, and had a slightly higher risk of recurrence/persistence; however, these differences were not significant and 71% of the recurrences were squamous cell carcinomas. Thus, in young Taiwanese women with stage Ib-IIa cervical cancer, the majority of deaths cannot be attributed to a specific HPV type or unique tumor morphology.

Adult↗

PubMed1997

Pulsatile ocular blood flow in eyes with untreated choroidal melanoma.

PURPOSE: To investigate the effect of choroidal melanoma on pulsatile ocular blood flow (POBF). METHODS: Seventeen patients (10 men and 7 women) with unilateral untreated choroidal melanoma and 22 controls matched for age and sex were studied. Intraocular pressure (IOP), pulse amplitude (PA) and POBF were measured using the OBF Tonograph. In each patient, mean inter-ocular differences were analysed using the paired t-test. The correlation coefficient between tumour thickness and POBF was calculated. To assess the variation of this parameter, the coefficient of variation for three repeated readings was determined for healthy and affected eyes. RESULTS: In the control group, there was no significant difference between eyes in any parameter. In patients with melanoma, there was no significant difference in IOP and PA between affected and unaffected eyes. Mean POBF was significantly higher in affected eyes (1040 microliters min-1) than unaffected eyes (876 microliters min-1) (p = 0.003). There was no correlation between tumour thickness and absolute POBF (r = -0.24) or between tumour thickness and inter-ocular difference in POBF between affected and unaffected eyes (r = -0.17). Mean coefficient of variation of three repeated readings of POBF was 7.76% in healthy eyes and 8.97% in affected eyes. CONCLUSIONS: These findings suggest a high tumour blood flow or a global increase in choroidal blood flow in the presence of melanoma. POBF measurement may be useful in the clinical assessment of eyes with choroidal melanoma.

Aged↗

PubMed1997

The A protein of the filamentous bacteriophage Cf of Xanthomonas campestris pv. citri.

Filamentous bacteriophages have very strict host specificities. Experiments were performed to investigate whether the A protein of the filamentous phage Cf, which infects Xanthomonas campestris pv. citri but not X. campestris pv. oryzae, is involved in determining Cf's host specificity. The gene encoding the A protein of Cf was cloned and expressed in X. campestris pv. citri. The genomic DNA of another filamentous bacteriophage, Xf, which infects X. campestris pv. oryzae but not X. campestris pv. citri, was then introduced by electroporation into X. campestris pv. citri that had expressed the A protein of Cf. The progeny phages thus produced were able to infect both X. campestris pv. oryzae and X. campestris pv. citri, indicating that the A protein of Cf was incorporated into the viral particles of Xf and conferred upon Xf the ability to infect the host of Cf. Inactivation of the A protein gene abolished the infectivity of Cf. The results of this study indicate that the A protein of Cf is responsible for controlling the host specificity of Cf.

Bacteriophages↗

PubMed1997

Differential development of the enhanced metabolic response during amphetamine sensitization.

Behavioral sensitization elicited by repeated administration of amphetamine does not fully develop until a period after discontinuation of amphetamine, but then persists undiminished for a long time. This experiment investigated the regional metabolic changes in rats pretreated with amphetamine and challenged after different abstinence periods (2, 7 and 28 days), using the 2-[14C]deoxyglucose method. The results demonstrated that chronic amphetamine administration enhanced rates of local cerebral glucose utilization in specific cerebral regions. The magnitude and distribution of effects varied with the abstinence period. A challenge dose of d-amphetamine 2 days after pretreatment was found to have no more, or only mildly elevated, local cerebral glucose utilization compared with that following a single acute dose. In rats challenged at the 7th and 28th day, a supersensitive metabolic response was found in dopaminergic and non-dopaminergic areas. This finding suggested regional differences in the development of sensitization and underscored the importance of an abstinence period in the study of sensitization and amphetamine psychosis.

Amphetamine↗

PubMed1997

Age and sex effects on HbA1c. A study in a healthy Chinese population.

OBJECTIVE: To evaluate whether glycohemoglobin levels increase with age in both sexes and to determine the effect of BMI on this increment. RESEARCH DESIGN AND METHODS: A cross-sectional survey of 4,580 healthy Chinese men and women, aged 20-85 years, was performed. All subjects who did not have identifiable diseases and who were not on medication known to influence glucose tolerance were recruited from participants at the preventive services of the National Cheng-Kung University Hospital. As an indicator of plasma glucose levels, glycohemoglobin was measured. The subjects were classified according to their age and BMI for both men and women, and any relationships with glycohemoglobin levels were evaluated. RESULTS: In all the BMI groups divided into quartiles, glycohemoglobin levels increased with age. The largest elevation of glycohemoglobin was observed in the 45- to 54-year-old age-group, except in men with a BMI between the lowest and highest quartiles. The group with a BMI above the highest quartile had a higher glycohemoglobin than the group with a BMI below the lowest quartile in men aged < 54 years and women aged 35-64 years. Men had higher average glycohemoglobin levels than women < 55 years of age. CONCLUSIONS: The age factor itself may cause an elevation in glycohemoglobin independent of other age-related factors in Chinese men and women, and there is a sex difference with a lower average glycohemoglobin level in women before menopause. Furthermore, BMI, but not a family predisposition to diabetes or leisure-time physical activity, affects this age-dependent increase in glycohemoglobin levels.

Adult↗

PubMed1997

Molecular subtyping of human T-lymphotropic virus type I (HTLV-I) by a nested polymerase chain reaction-restriction fragment length polymorphism analysis of the envelope gene: two distinct lineages of HTLV-I in Taiwan.

The major type of human T-lymphotropic virus type I (HTLV-I), generally referred to as the cosmopolitan type, has been grouped into three subtypes (A, B, and C) by phylogenetic analysis of the long terminal repeat sequences of the viral genome. Twelve subtype-specific nucleotide variations have been deduced by comparison between the envelope (env) sequences of 16 HTLV-I strains with defined subtypes and 9 Taiwanese HTLV-I strains. To gain further insights into the molecular epidemiology of HTLV-I and the origin of this virus in Taiwan, a rapid method of identification for the cosmopolitan subtypes was developed by using a nested polymerase chain reaction (PCR) and subsequent restriction fragment length polymorphism (RFLP) studies using the two subtype B-specific and four subtype C-specific nucleotides located within the positions 5708 to 6320 of the envgene. The nested PCR-RFLP method was used to subtype HTLV-I from four virus-positive cell lines derived from 1 Japanese and 3 North American patients, as well as 41 blood-unrelated Taiwan Chinese. The sequences of PCR products were determined and the six positions of subtype-specific nucleotide variations were examined. The sequence data completely supported the subtyping data via the nested PCR-RFLP method. The results demonstrated that, as is the case in Japan, at least two distinct cosmopolitan subtypes (A and B) of HTLV-I were present in Taiwan, but the more prevalent subtype in Taiwan is A in contrast to subtype B in Japan. Furthermore, rapid subtyping could facilitate molecular epidemiological studies of HTLV-I infection and linkage between HTLV-I subtypes and virus-associated diseases.

Base Sequence↗

PubMed1997

Pulsatile ocular blood flow measurements in healthy eyes: reproducibility and reference values.

PURPOSE: To determine the reproducibility and the normal reference range of pulsatile ocular blood flow (POBF) values in healthy subjects using the Ocular Blood Flow Tonograph (OBF Laboratories, UK Ltd., Wiltshire, England). METHOD: Pulsatile ocular blood flow was measured in one eye of each of 83 patients. Coefficient of reliability was determined by calculation of intraclass correlation coefficient via one-way analysis of variance. Mean difference between measurements was calculated for bias and first exposure effects. Pulsatile ocular blood flow from 163 healthy individuals were analyzed to determine the distribution, mean, standard deviation (SD), range, and the 5th and 95th percentile values. The influence of age, blood pressure, pulse rate, and intraocular pressure on pulsatile ocular blood flow was determined by regression analysis. RESULTS: Reliability coefficient for pulsatile ocular blood flow values ranging from 290 microliters/min to 2,196 microliters/min was 0.92. Variation in bias and first exposure effect were not significant. Pulsatile ocular blood flow values were normally distributed. Mean values were 669.90 +/- 233.0 microliters/min in men and 841.90 +/- 254.6 microliters/min in women. Fifth and ninety-fifth percentile values were 364.75 microliters/min and 1,266.10 microliters/min in men and 397.18 microliters/min and 1,346.10 microliters/min in women. Pulsatile ocular blood flow was significantly influenced by pulse rate. CONCLUSION: This study confirms the reliability of the Ocular Blood Flow Tonograph in repeated measurements of POBF within individuals over short time intervals. The high interindividual variation in POBF may invalidate comparison of POBF between individuals, and the wide range of normal values may limit the value of using a low POBF as a possible indicator of disease.

Adult↗

PubMed1997

Human T-lymphotropic virus type II infection in Vietnamese thalassemic patients.

Anti-human T-lymphotropic virus type I/II (HTLV-I/II) antibodies were screened by particle agglutination test in a total of 66 patients with thalassemia major who received multiple transfusion from paid donors at the Blood Transfusion Hematology Center of Ho Chi Minh City in South Vietnam. HTLV-II infection was confirmed in 6 patients (9.1%) by Western blot analysis and/or polymerase chain reaction. Phylogenetic analysis revealed that long terminal repeat sequences of HTLV-II proviruses from 5 thalassemic patients in Vietnam belonged to the same phylogenetic subgroup of HTLV-IIb as those from intravenous drug abusers in North America and Europe. These data shed light on the route of introducing HTLV-II into Vietnam.

Adolescent↗

PubMed1996

A specific association of ERK3 with B-Raf in rat hippocampus.

The possible formation of a stable complex between extracellular signal-regulated kinases (ERKs) and Raf protein kinases was investigated in an attempt to understand the molecular mechanism by which Raf protein kinases were differentially regulated in response to the various stimuli, leading to the activation of ERKs in rat hippocampus. ERK3 was found to coelute with B-Raf, but not c-Raf1, after fractionation of rat hippocampal lysates by QMA anionic exchange chromatography. ERK3 was released into soluble supernatant fraction from the B-Raf, but not c-Raf1, immunoprecipitate, after incubation with ATP. These results, taken together, suggest the specific association of ERK3 with B-Raf in rat hippocampus.

Animals↗

PubMed1996

Coagulation factor Xa stimulates platelet-derived growth factor release and mitogenesis in cultured vascular smooth muscle cells of rat.

The mitogenic effect of activated coagulation factor X (factor Xa) was examined in cultured aortic smooth muscle cells (VSMC) from Wistar-Kyoto rats (WKY). Factor Xa stimulated DNA synthesis and cell growth in VSMC, not through the phospholipase C-protein kinase C pathway because increase of inositol monophosphate (IP) accumulation and intracellular Ca2+ concentration was not observed, but probably via the PDGF receptor tyrosine kinase pathway since the pathway's components, Ras, Raf-1, MAPK (both 42 and 44 kD), and the transcription factors, c-Fos and c-Jun, were activated. These appeared to be effected by the serine protease activity of factor Xa, since in the presence of serine protease inhibitors such as PMSF, leupeptin, benzamidine, TAP anticoagulant, and TLCK, the latter three being specific inhibitors of the factor Xa, active site, the effects were completely blocked. Anti-factor Xa mAb, 5224, which specifically negated the activity of factor Xa, also inhibited completely the mitogenic effect of factor Xa, but not that of thrombin. Addition of PDGF did not affect the effect of factor Xa, which, however, was inhibited by anti-PDGF-AB antibody. This observation and the activation of PDGF receptor tyrosine kinase pathway suggested that the factor Xa might exert its effect via PDGF-like function. Direct measurement confirmed that factor Xa stimulated the release of PDGF from VSMC. Factor Xa, therefore, exerts serine protease activity on VSMC, causing somehow the release of PDGF, that in turn acts on the PDGF receptor tyrosine kinase; the pathway is then turned on, leading eventually to DNA synthesis and cell proliferation.

Animals↗

PubMed1996

Complex formation of JAK2 with PP2A, P13K, and Yes in response to the hematopoietic cytokine interleukin-11.

Interleukin-11 is a stromal derived cytokine important in hematopoiesis. IL-11 intracellular signaling travels through cytoplasmic kinases of the Janus family. How JAKs accomplish the multiple functions of IL-11 has not been determined and until recently only a few associated downstream proteins have been identified. We present evidence here for the IL-11 induced association of PP2A, P13K, and Yes to JAK2. Reciprocal immunoprecipitations support the mutual involvement of these signaling components in IL-11 mediated signal transduction. This novel finding of JAK2/PP2A binding and release may have relevance to many serine/threonine regulated mechanisms such as P13K, Stat, and MAPK activation. These associations support a model of JAK2 as a protein kinase docking protein of IL-11 signal transduction that may be applicable to other gp130 and JAK signal transduction systems.

3T3 Cells↗

PubMed1996

Multiple transcription factors are required for activation of human interleukin 9 gene in T cells.

The genetic elements and regulatory mechanisms responsible for human interleukin 9 (IL-9) gene expression in a human T cell leukemia virus type I-transformed human T cell line, C5MJ2, were investigated. We demonstrated that IL-9 gene expression is controlled, at least in part, by transcriptional activation. Transient expression of the luciferase reporter gene linked to serially deleted sequences of the 5'-flanking region of the IL-9 gene has revealed several positive and negative regulatory elements involved in the basal and inducible expression of the IL-9 gene in C5MJ2 cells. An AP-1 site at -146 to -140 was shown to be involved in the expression of the IL-9 gene. A proximal region between -46 and -80 was identified as the minimum sequence for the basal and inducible expression of the IL-9 gene in C5MJ2 cells. Within this region, an NF-kappaB site at -59 to -50 and its adjacent 20-base pair upstream sequence were demonstrated to play a critical role for the IL-9 promoter activity. DNA-protein binding studies indicated that NF-kappaB, c-Jun, and potentially novel proteins (around 35 kDa) can bind to this important sequence. Mutations at different sites within this proximal promoter region abolished the promoter activity as well as the DNA binding. Taken together, these results suggest that the cooperation of different transcription factors is essential for IL-9 gene expression in T cells.

Base Sequence↗