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Biomedical subjects

Y F Yang

Publications and source records attributed to Y F Yang.

At least 55 records · Page 3Linked to original sources
PubMed1996

Overexpression of the proto-oncogene c-jun in association with low-risk type specific human papillomavirus infection in condyloma acuminata.

Infection with different types of human papillomavirus (HPV) is associated with neoplasia at different anatomic sites. The "low-risk" HPVs (LR-HPV) are responsible for benign genital lesions such as condyloma acuminata. In order to clarify the tumorigenic mechanism of LR-HPV, the HPV infection status was investigated and the expression of the c-jun proto-oncogene in different HPV-related skin and genital lesions analyzed. Of the 17 condyloma specimens analyzed by Western blotting, 13 cases (76.5%) exhibited overexpression of the c-jun gene. All 13 cases harbored high copy numbers of the LR-HPV genome with an average of 926 copies per cell, whereas the other four cases had an average of 12 copies of LR-HPV per cell (P < 0.001). Further typing of HPV by Southern blotting revealed that HPV-6 and HPV-11 infections predominated in c-jun positive cases. The c-jun protein was detected much less frequently in cervical cancers (three of 29, or 10.3%) and skin warts (one of 10), and was not detected in five genital polyps or in five normal cervical tissues. These findings suggest a type 6/11-specific induction of c-jun gene expression in HPV-related neoplastic lesions.

Animals↗
PubMed1996

When to discharge patients with bleeding peptic ulcers: a prospective study of residual risk of rebleeding.

BACKGROUND: From January 1993 to December 1994, we conducted a prospective study to investigate the evolutionary change of rebleeding risk in bleeding peptic ulcers. To obviate possible confounding factors that would influence decision making for discharge of patients, subjects with coexistent acute illnesses, systemic bleeding disorders, alcoholism, and use of nonsteroidal anti-inflammatory drugs were excluded. METHODS: Emergency endoscopies were performed in patients with hematemesis or a melena within 24 hours of admission. Ulcer lesions were divided into six categories according to endoscopic findings. The residual risks of rebleeding of each type of ulcers were calculated for 10 days, and the critical point of acceptable rebleeding risk after discharge was set at 3%. RESULTS: Three hundred ninety-two patients with bleeding peptic ulcers completed the study. The ulcers, characterized by clean bases, red or black spots, adherent clots, nonbleeding visible vessels without local therapy, nonbleeding visible vessels with local therapy, and bleeding visible vessels with local therapy took 0, 3, 3, 4, 4, and 3 days, respectively, to decrease rebleeding risk to below the critical point. All episodes of fatal rebleeding (n = 4) occurred within 24 hours after admission. CONCLUSIONS: Patients with clean-based ulcers can be discharged in the first day of admission. The optimal duration required for hospitalization of patients with ulcers characterized by nonbleeding visible vessels at initial endoscopy is 4 days. The remaining patients with ulcers marked by other bleeding stigmata may be discharged after a 3-day observation.

Adolescent↗
PubMed1996

Coincidental expression of E5a and c-jun in human papillomavirus type 6/11-infected condylomata.

Previously, we have shown that E5a can induce expression of the c-jun gene in human papillomavirus (HPV)-11 E5a transformed NIH 3T3 cells and human epidermal keratinocytes. In this study, we investigated the relationship between expression of the E5a gene and c-jun in pathologically confirmed condylomata specimens using mRNA hybridization in situ. The c-jun RNA concentration was significantly higher in condylomata specimens with E5a mRNA expression than in specimens without E5a mRNA expression, or in normal cervical specimens. The cells with c-jun expression were located predominantly in the basal and parabasal cell layers. These layers were also the primary location of E5a-expressing cells. This is the first demonstration of a strong correlation (74%) between expression of the E5a and c-jun genes in condylomata specimens. This correlation might reflect regulation by HPV-11 E5a of c-jun gene expression in condyloma.

3T3 Cells↗
PubMed1996

Comparisons of long-term effects of lisinopril vs nifedipine vs conventional therapy in the treatment of mild-to-moderate hypertension in patients with chronic obstructive pulmonary disease.

BACKGROUND: Any hypertensive patient may be found to have associated lung disease. The response of high blood pressure to specific antihypertensive agents in this category is still unknown. Thus, a group of 76 consecutive patients with mild-to-moderate hypertension and chronic obstructive pulmonary disease (COPD) were selected to participate in a clinical antihypertensive trial to define the roles of lisinopril, nifedipine and conventional therapy, and their impact on the renin-antiotensin system (RAS). METHODS: After a two-week placebo period, patients were randomly assigned to a regimen of one of three main treatment strategies: (A) lisinopril with or without diuretics; (B) nifedipine with or without diuretics; or (C) diuretics with or without conventional vasodilators (sorbitrate and hydralazine) or selective beta-blockers. The drug doses were titrated to a goal of less than 90 mmHg for maximal diastolic pressure, and the patients continued to receive therapy for at least one year. RESULTS: After one year of follow-up, only 66 patients had completed the study. All high blood pressure was significantly reduced by the three regimens (p < 0.005), but no significant difference in blood pressure control by any individual regimen was noted. Double product also showed the similar trend. Therapy A achieved the best reduction of double product among three regimens, but statis tieally insignificant. Furthermore therapy A suppressed the RAS, whereas therapies B and C might activate this system. Concomitantly, therapy A also had significant favorable effects on metabolic responses in contrast to therapy C. Therapy B revealed a neutral effect on such responses. CONCLUSIONS: These data indicated that these three main strategies could provide significant antihypertensive efficacy for blood pressure control in patients with hypertension and COPD. For preventive strategy, therapy A may provide more advantageous effects than therapy C. A long-term double-blind trial including more subjects is warranted to identify the true advantages of therapy A in reduction or major cardiovascular and respiratory events.

Aged↗
PubMed1996

Cross-talk between thyroid hormone and specific retinoid X receptor subtypes in yeast selectively regulates cognate ligand actions.

Thyroid (T3) hormone beta1 (TR) and 9-cis retinoic acid (9c-RA) retinoid X receptors (RXR) can form heterodimer complexes that bind to hormone response elements (HREs) in target genes to either activate or repress transcription. However, the action of each cognate ligand and the accessory cellular factors that can differentially regulate the transcriptional responses of a heterodimer-DNA complex are not well understood. Studies in most mammalian cell lines have demonstrated that 9c-RA cannot bind or transactivate TR/RXR-T3 response element (TRE) complexes. In contrast, when identical heterodimer complexes were coexpressed in the yeast (Saccharomyces cerevisiae) with single copy typical TREs [i.e., DR+4 (direct repeat), F2 (everted repeat), or PAL (inverted repeat) DNA response elements] we observed that i) unliganded TRbeta1 homodimers had constitutive action on F2 and PAL but not DR4 TREs; ii) TRbeta1 homodimer responsivity to T3 ligand was relatively weak (less than twofold) and was only demonstrable on F2 but not PAL or DR4-TREs, whereas TRbeta1 heterodimers responded to T3 when RXRgamma but not RXR alpha was the heterodimeric partner; iii) RXR responsivity to 9c-RA (three- to sixfold) could be demonstrated only on palindromic TREs that could be enhanced by TRbeta1 on all TREs; iv) T3 + 9c-RA ligands increased (additively or synergistically) transactivation when RXRgamma but not alpha heterodimerized with TRbeta1 on both typical as well as atypical (DR1, DR3, DR5, and F2M) TREs. Substitutions for wild-type TRbeta1 of C-terminus mutants deficient in dimerization with RXRs abrogated the anticipated single and dual cognate ligand-induced effects on TRbeta1/RXRgamma transactivation of DR4 TREs, whereas mutants with preserved dimerization function but impaired T3 transactivation regions could maintain an enhanced 9c-RA response but were devoid of the anticipated T3 and dual (T3 + 9c-RA) cognate ligand-induced effects. Thus, the ligand-inducible response of TR and RXR homodimers expressed in yeast are relatively weak but can be further enhanced by TRbeta1 cross-talk with specific RXR subtypes in the presence of both cognate ligands.

Animals↗
PubMed1996

[Comparison between two types of air microorganism sampling].

The airflow striking sampling was compared with flat utensils sedimentation sampling for collection of air microorganisms. The result showed that air microorganism count with the former method is more efficient than the latter method (P < 0.05). The flat utensils sedimentation sampling only collected larger particles of microorganism so the air microorganism count was not accurate. However, it is still a suitable method in hygiene without other choices. The airflow striking sampling collected more middle and tiny particles for air microorganism than the sedimentation sampling and can accurately show microorganism content in air, so it is an optimal sampling method.

Air Microbiology↗
PubMed1995

Immunogenicity of transgenic plant-derived hepatitis B surface antigen.

The focus of the Children's Vaccine Initiative is to encourage the discovery of technology that will make vaccines more readily available to developing countries. Our strategy has been to genetically engineer plants so that they can be used as inexpensive alternatives to fermentation systems for production of subunit antigens. In this paper we report on the immunological response elicited in vivo by using recombinant hepatitis B surface antigen (rHBsAg) purified from transgenic tobacco leaves. The anti-hepatitis B response to the tobacco-derived rHBsAg was qualitatively similar to that obtained by immunizing mice with yeast-derived rHBsAg (commercial vaccine). Additionally, T cells obtained from mice primed with the tobacco-derived rHBsAg could be stimulated in vitro by the tobacco-derived rHBsAg, yeast-derived rHBsAg, and by a synthetic peptide that represents part of the a determinant located in the S region (139-147) of HBsAg. Further support for the integrity of the T-cell epitope of the tobacco-derived rHBsAg was obtained by testing the ability of the primed T cells to proliferate in vitro after stimulation with a monoclonal anti-idiotype and an anti-idiotype-derived peptide, both of which mimic the group-specific a determinant of HBsAg. In total, we have conclusively demonstrated that both B- and T-cell epitopes of HBsAg are preserved when the antigen is expressed in a transgenic plant.

Amino Acid Sequence↗
PubMed1995

Limited regulatory effect of T cell receptor-derived peptides.

T cell receptor (TCR)-derived peptides have been used to induce regulatory T cells which recognize T cells of specific elements and downregulate the autoimmune response. Consistent with these observations, priming of peptides corresponding to V beta 8 complementarity-determining region 2 (CDR2) was found to specifically suppress the proliferation of V beta 8+ T cells in the draining lymph nodes. Similarly, the generation of V beta 8-dominant T cell responses was prevented locally by vaccination with V beta 8 CDR2 peptides. There was a good correlation between the downregulation of V beta 8+ T cells and the inhibition of the corresponding T cell responses in different lymphoid tissues. No systemic inhibition could be detected even after an interval which would allow the redistribution of the "regulatory T cells." T cells specific for V beta 8 CDR2 peptides was generated following peptide immunization. However, the appearance of these TCR peptide-specific T cells was independent of the downregulation of V beta 8+ T cells. The transient and localized inhibitory effects of TCR-derived peptides indicate that these peptides have very limited use in regulating specific T cell response.

Amino Acid Sequence↗
PubMed1995

A comparison of the antibody and T cell response elicited by internal image and noninternal image anti-idiotypes.

We have previously reported that several monoclonal anti-idiotypes were generated against a syngeneic monoclonal antibody designated H3F5 (idiotype) which recognizes the protective "a"-determinant on hepatitis B surface antigen (HBsAg). In the present study, we compared the humoral and cellular response to HBsAg by immunizing Balb/C mice with four of these anti-Ids. We observed that two internal image and one noninternal image anti-Ids can act as surrogates for HBsAg. Following immunization with these anti-Ids, high levels of anti-HBs antibodies were elicited. Three of the anti-Ids could also prime T cell for an HBsAg-specific proliferative response, the two internal image anti-Ids elicited much stronger T cell responses to HBsAg than the non-internal image anti-Id. One noninternal image anti-Id did not generate any anti-HBs antibody response and could not elicit an HBsAg-specific T cell proliferative response. All four anti-Ids could elicit immunoglobulin which was H3F5-idiotype positive. This study further supports the concept that some monoclonal anti-Ids can mimic at both the B and T cell level the properties of a nominal antigenic epitope.

Animals↗
PubMed1995

Immunological evaluation of three generations of anti-idiotype vaccine: study of B and T cell responses following priming with anti-idiotype, anti-idiotype peptide and its MAP structure.

A 15mer peptide (2F10 peptide) is capable of mimicking the group specific "a" determinant of human hepatitis B surface antigen (HBsAg), both at the B and T cell level. This peptide represents a sequence on the heavy-chain hypervariable region of a monoclonal "internal image" anti-idiotype (anti-id) 2F10 that has partial sequence homology to the "a" determinant epitope of HBsAg. In order to potentiate the immunological properties of 2F10 peptide, a synthetic polymer of the 2F10 peptide was constructed (2F10 MAP). In this study we present the immunological evaluation of three generations of anti-idiotype vaccines, namely the 2F10 anti-id, 2F10 peptide and 2F10 MAP. Our results indicate that there is significant anti-HBs production in mice immunized with 2F10 anti-id or 2F10 MAP, in comparison to mice immunized with the linear monomeric 2F10 peptide. In priming experiments we found that only 2F10 antibody or 2F10 MAP (both at a suboptimal dose), could effectively prime B cells in vivo which could be efficiently recalled by challenge with a suboptimal dose of HBsAg. Collectively our findings indicate that 2F10 MAP retains all the immunological properties of the intact anti-id, and is qualitatively similar and quantitatively superior to the linear monomeric 15mer 2F10 peptide. The 2F10 MAP is the smallest MAP structure composed of a naturally occurring contiguous sequence having both a B and T cell epitope capable of eliciting a response to the native antigen.

Amino Acid Sequence↗
PubMed1995

Brain serotonin depletion attenuates diabetogenic effects of streptozotocin.

The diabetogenic effects of streptozotocin (STZ) were studied on blood glucose, plasma insulin, feeding and drinking, body weight, islet morphology, and hypothalamic serotonin (5-HT) release in vehicle-pretreated rats and in rats pretreated with either intracerebroventricular injection of 5,7-dihydroxytryptamine (5,7-DHT; a 5-HT nerve fiber depletor), intraperitoneal injection of p-chlorophenylalanine (PCPA; a tryptophan hydroxylase inhibitor), or intraperitoneal injection of p-chloroamphetamine (PCA; a neurotoxin for 5-HT nerve fiber). At four days after STZ administration, vehicle-treated rats displayed hyperglycemia, polydipsia, polyphagia, decreased plasma insulin level, derangement of islet morphology (few insulin cells, accumulation of glucagon cells), and elevated 5-HT release in the hypothalamus. The above diabetogenic effects of STZ were attenuated by brain serotonin depletion induced by 5,7-DHT, PCPA, or PCA. Furthermore, the STZ-induced hyperglycemia or derangement of islet morphology was attenuated by peripheral sympathectomy or adrenalectomy. It is concluded that brain serotonin depletion attenuates diabetogenic effects of STZ by reducing sympathetic efferent activity in rats.

5,7-Dihydroxytryptamine↗
PubMed1995

Reappraisal of continuous positive airway pressure therapy in acute cardiogenic pulmonary edema. Short-term results and long-term follow-up.

To investigate whether serial incremental continuous positive airway pressure (CPAP) has any short-term or long-term advantages over face-mask oxygen therapy by way of intrapulmonary shunt reduction, 100 patients admitted to the coronary care unit for the treatment of acute cardiogenic pulmonary edema were studied. All patients received Swan-Ganz catheterization. Hemodynamic and pulmonary function parameters were recorded over the next 6 h, and the patients were followed until hospital discharge. All survivors received regular follow-up at 1-month intervals in the outpatient clinic. During the first-stage investigation period (3 h) PaO2 in the CPAP group showed a significant increase, whereas the intrapulmonary shunt and alveolar-arterial oxygen tension gradient (P[A-a]O2) was significantly reduced (p < 0.005). The CPAP group had significantly lower rate-pressure product and higher stroke volume index compared with the control group. The therapeutic failure rate over 6 h was 24% in the CPAP group and 50% in the control group (p < 0.01). The CPAP group had a significantly lower incidence of tracheal intubation and ventilator therapy than the control group; however, there was no significant difference in short-term mortality and hospital stay between the two groups. In conclusion, although study size was not large enough to demonstrate a difference in mortality, CPAP therapy resulted in physiologic cardiovascular and pulmonary function improvement and significantly reduced the need for intubation; however, it did not decrease mortality in patients with acute cardiogenic pulmonary edema, and a much larger study is needed to investigate this possibility.

Acute Disease↗
PubMed1995

[Preliminary analysis of relationship between immunological changes and syndrome differentiation-typing in traditional Chinese medicine and prognosis with chronic idiopathic thrombocytopenic purpura].

In order to study the relationship between the basement immunological changes, TCM Syndrome Differentiation and prognosis, alkaline phosphates antialkaline phosphatase (APAAP) and ELISA assay were used to determine the T lymphocyte subsets, the platelet associated antibody (PAIgG, PAIgA, PAIgM) and plasma antiplatelet-autoantibodies (GP II b, GP III a, GP I b) in 55 chronic idiopathic thrombocytopenic purpura (ITP) and 53 healthy subjects as control. The results indicated that the immunological changes was closely related to the prognosis, while the TCM Syndrome Differentiation was also related to it, which denoted that it is significant to investigate both factors in guiding treatment and assessing the prognosis.

Adolescent↗
PubMed1994

Effects of E5a and E7 genes of human papillomavirus type 11 on immortalized human epidermal keratinocytes and NIH 3T3 cells.

The E5a gene of HPV-11 expressed in NIH 3T3 cells led to tumorigenesis in nude mice; whereas when expressed in keratinocytes, E5a induced anchorage independent growth, but was nontumorigenic in nude mice. The E7 gene of HPV-11 expressed NIH 3T3 cells led to tumors in nude mice and morphological transformation, but not anchorage independent growth. Keratinocytes expressing the E7 gene induced colony formation in soft agarose, but not tumorigenesis in nude mice. Comparison of transforming activities of HPV-11 E5a and E7 genes of HPV-11 showed that the efficiency of cell transformation by E7 was weaker than that of E5a.

3T3 Cells↗
PubMed1994

Genital human papillomavirus infections in Taiwan.

OBJECTIVES: Identification and typing of HPV infections in genital condyloma and normal cytological cervix. METHODS: Cervical cells from 289 Pap cases with normal cytological findings were examined for HPV infection by slot blot hybridization. Fifteen condyloma biopsy specimens were studied by Southern blot hybridization. RESULTS: Thirty-six cases (12.5%) with normal cervical cytology were HPV positive. The predominant HPV type in women with normal cytology is HPV-16. Risk factors for HPV infection in women with normal cytology depend on age and history of pregnancies. Twelve cases (80%) of condyloma contained HPV-6 or -11 sequences. The predominant HPV type in genital condyloma is HPV-11. CONCLUSIONS: HPV detection in population-based screening programs for cervical neoplasia can be an important tool in identifying women who are at risk of developing dysplasia and cervical cancer.

Adult↗
PubMed1994

The long-term stone recurrence rate and renal function change in unilateral nephrectomy urolithiasis patients.

We evaluated the stone recurrence rate and long-term renal function in 50 patients with a solitary kidney 60 to 84 months (mean 70.6) after unilateral nephrectomy for urinary tract stone disease. Followup evaluation included a detailed history, physical examination, blood and urine biochemistry studies, urinalysis, urine culture, excretory urography, ultrasonography of the kidney and 131iodine-ortho-iodohippurate renography. The overall stone recurrence rate in unilateral nephrectomy urolithiasis patients was 30% (15 of 50). The mean interval until stone recurrence was 31.1 months (range 6 to 74) and the mean episodes of recurrence were 2.1 times per patient (range 1 to 5). Function of the remnant kidney in most patients was unchanged during followup. However, 2 of the 15 patients with recurrent stones had anuria during the acute attack of renal colic and, thus, required percutaneous nephrostomy urinary diversion, while 1 had proteinuria (3 gm. per day) and progressive renal failure 47 months after nephrectomy. The metabolic stone patients seemed to experience recurrence more easily than metabolic stone patients seemed to experience recurrence more easily than infection stone patients (37% versus 13%) but no statistically significant difference was noted (p = 0.198).

Adult↗