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S C Yang

Publications and source records attributed to S C Yang.

At least 55 records · Page 3Linked to original sources
PubMed1999

Molecular detection of tumor cells in bronchoalveolar lavage fluid from patients with early stage lung cancer.

BACKGROUND: Conventional cytologic analysis of sputum is an insensitive test for the diagnosis of non-small-cell lung cancer (NSCLC). We have recently demonstrated that polymerase chain reaction (PCR)-based molecular methods are more sensitive than cytologic analysis in diagnosing bladder cancer. In this study, we examined whether molecular assays could identify cancer cells in bronchoalveolar lavage (BAL) fluid. METHODS: Tumor-specific oncogene mutations, CpG-island methylation status, and microsatellite alterations in the DNA of cells in BAL fluid from 50 consecutive patients with resectable (stages I through IIIa) NSCLC were assessed by use of four PCR-based techniques. RESULTS: Of 50 tumors, 28 contained a p53 mutation, and the identical mutation was detected with a plaque hybridization assay in the BAL fluid of 39% (11 of 28) of the corresponding patients. Eight of 19 adenocarcinomas contained a K-ras mutation, and the identical mutation was detected with a mutation ligation assay in the BAL fluid of 50% (four of eight) of the corresponding patients. The p16 gene was methylated in 19 of 50 tumors, and methylated p16 alleles were detected in the BAL fluid of 63% (12 of 19) of the corresponding patients. Microsatellite instability in at least one marker was detected with a panel of 15 markers frequently altered in NSCLC in 23 of 50 tumors; the identical alteration was detected in the BAL fluid of 14% (three of 22) of the corresponding patients. When all four techniques were used, mutations or microsatellite instability was detected in the paired BAL fluid of 23 (53%) of the 43 patients with tumors carrying a genetic alteration. CONCLUSION: Although still limited by sensitivity, molecular diagnostic strategies can detect the presence of neoplastic cells in the proximal airway of patients with surgically resectable NSCLC.

Alleles↗
PubMed1999

Targeting of aminopeptidase N to bile canaliculi correlates with secretory activities of the developing canalicular domain.

We have used human hepatoma cell lines as an in vitro model to study the development of hepatic bile canaliculi (BC). Well-differentiated hepatoma cells cultured for 72 hours could develop characteristic spheroid structures at sites of cell-cell contact that contained tight junctions and various membrane protein markers, resembling BC found in vivo. Intact cytoskeleton was essential for this differentiation process. In the coculture experiments in which cells of different origins were populated together, BC only formed between hepatic cells and preferentially among well-differentiated cells. Poorly differentiated hepatoma cells never formed BC among themselves, but could be induced to undergo canalicular differentiation by interacting with well-differentiated cells. During BC morphogenesis, integral canalicular membrane proteins were gradually delivered and accumulated at the developing BC. Among them, targeting of aminopeptidase N (APN) seemed to correlate with activation of certain secretory functions. Specifically, only APN-positive BC supported excretion of fluorescein diacetate (FDA) and 70-kd dextran, but had no relationship with secretion of horseradish peroxidase (HRP). Targeting of another BC protein, dipeptidyl peptidase IV (DPPIV), on the other hand, bore no association with any secretory activity examined. In addition, inhibition of enzymatic activity of APN could perturb canalicular differentiation without affecting cell proliferation. Our results suggest that targeting of APN proteins may reflect or even play an important role in the development and functional maturation of the canalicular structures.

Bile Canaliculi↗
PubMed1999

Cyclin D1 overexpression is an indicator of poor prognosis in resectable non-small cell lung cancer.

Cyclin D1 is one of the G1 cyclins that control cell cycle progression by allowing G1 to S transition. Overexpression of cyclin D1 has been postulated to play an important role in the development of human cancers. We have investigated the correlation between cyclin D1 overexpression and known clinicopathological factors and also its prognostic implication on resected non-small-cell lung cancer (NSCLC) patients. Formalin-fixed and paraffin-embedded tumour tissues resected from 69 NSCLC patients between stages I and IIIa were immunohistochemically examined to detect altered cyclin D1 expression. Twenty-four cases (34.8%) revealed positive immunoreactivity for cyclin D1. Cyclin D1 overexpression is significantly higher in patients with lymph node metastasis (50.0% vs 14.4%, P = 0.002) and with advanced pathological stages (I, 10%; II, 53.8%; IIIa, 41.7%, P = 0.048; stage I vs II, IIIa, P = 0.006). Twenty-four patients with cyclin D1-positive immunoreactivity revealed a significantly shorter overall survival than the patients with negativity (24.0 +/- 3.9 months vs 50.1 +/- 6.4 months, P = 0.0299). Among 33 patients between stages I and II, nine patients with cyclin D1-positive immunoreactivity had a much shorter overall survival (29.7 +/- 6.1 months vs 74.6 +/- 8.6 months, P = 0.0066). These results suggest that cyclin D1 overexpression is involved in tumorigenesis of NSCLCs from early stage and could be a predictive molecular marker for poor prognosis in resectable NSCLC patients, which may help us to choose proper therapeutic modalities after resection of the tumor.

Adult↗
PubMed1999

An outbreak of enterically transmitted non-A, non-E viral hepatitis.

Patients with isolated serum transaminase elevations of unknown cause are common in China. An outbreak of such disease took place in a technicians' school during 1996. To define the epidemic and determine the etiology, a study was carried out, which included investigation of epidemiological, clinical and histological features. The symptoms of this disease were mild. The major clinical feature was transaminase elevation, and all serum markers of known hepatitis viruses were negative. Although the course of disease in most patients was self-limiting, in a few it was prolonged and relapsed. Histological findings were mild portal hepatitis or non-specific reactive hepatitis. The disease first appeared in 1994, and this outbreak occurred after October 1996. A total of 381 people were affected and the prevalence was as high as 60.7%. Casual contact and small-scale food transmission were considered to be risk factors for infection and the epidemic was under control 2 months later following the introduction of preventive measures for gastroenteric infection. Viral genomic fragments from the so-called transfusion-transmitted virus (TTV) were detected in acute-phase sera and stool samples collected 2 weeks before onset. Therefore, this disease outbreak might be another form of enterically transmitted viral hepatitis, not related to hepatitis A and E.

Adult↗
PubMed1999

The loss of expression of transforming growth factor-beta receptors correlates with the histopathologic tumor grade in bladder transitional cell carcinoma patients.

Transforming growth factor-beta (TGF-beta), a pleiotropic growth factor, is a potent inhibitor of cellular proliferation in cells of epithelial origin. Recently, it has been suggested that a loss of sensitivity to TGF-beta through a loss of expression of TGF-beta receptors T beta R-I and T beta R-II--is associated with tumor initiation and progression. Therefore, to investigate the relationship between TGF-beta receptors expression and carcinogenesis of bladder TCC, this study examined the expression of T beta R-I and T beta R-II in 46 bladder TCC patients using immunohistochemistry. Since histopathological grade is a widely accepted marker of prognosis, the results were compared in relation to the three grades of bladder TCC. The results demonstrated that the loss of TGF-beta receptors expression is associated with increasing histopathological grades of bladder TCC. Specifically, both T beta R-I and T beta R-II were readily detected in all 10 normal bladder mucosa specimens. Likewise, all 6 specimens of grade I TCC samples expressed high levels of both TGF-beta receptors. However, among grade II TCC samples, T beta R-I and T beta R-II were detected in 78% and 89%, respectively: among grade III TCC samples, T beta R-I and T beta R-II were detected in 45% and 41%, respectively. These results suggested that loss of sensitivity to TGF-beta may play a role in the progression of TCC from low to high grade disease.

Adult↗
PubMed1999

Laparoscopy-assisted urologic surgery through minilaparotomy.

Minimally invasive surgery has gained wide acceptance as a method of reducing postoperative pain and curtailing the convalescence period. We have devised a modified surgical technique of laparoscopy-assisted surgery through minilaparotomy. It is a hybridized form of conventional open and laparoscopic surgery and it combines the benefits of both techniques by reducing postoperative pain and scarring as in laparoscopy, but at the same time maintaining the safety of conventional open surgery. From January 1992 to September 1999, we performed laparoscopy-assisted surgery through minilaparotomy in 167 patients. The operative time for laparoscopy-assisted surgery through minilaparotomy ranged from 79 to 290 minutes (mean 125). There was no conversion to open surgery, no peri- or postoperative complications, and only 3 patients needed a blood transfusion at any stage. Pain was significant on the first day but resolved quickly. All patients resumed consistent oral intake on the second day. All patients commenced ambulation by the second postoperative day and were able to resume full ambulatory activity by the fourth postoperative day. The final would size did not exceed 10 cm in size and all patients expressed satisfaction with their wounds. In conclusion, we believe that laparoscopy-assisted minilaparotomy surgery is a truly minimally invasive technique maintaining the advantages of conventional surgery. Our method could become a first-line approach for simple nephrectomy, living donor nephrectomy and radical nephrectomy, as well as surgery for kidney and ureter stones.

Adolescent↗
PubMed1998

Serial analysis of gene expression in non-small cell lung cancer.

We used the serial analysis of gene expression (SAGE) method to systematically analyze transcripts present in non-small cell lung cancer. Over 226,000 SAGE tags were sequence analyzed from two independent primary lung cancers and two normal human bronchial/tracheal epithelial cell cultures. A total of 226,000 SAGE tags were sequence identified, representing 43,254 unique transcripts. Comparison of the tags present in the tumor with those identified in the normal tissue revealed 175 transcript tags that were overrepresented in the normal tissue and 142 tags that were overexpressed in the tumor by 10-fold or more. Northern hybridization was performed on 15 of the most abundantly expressed tags identified in the tumors. These tags were derived from either a known gene or a matched expressed sequence tag clone. The transcripts for 3 of the 15 genes, PGP 9.5, B-myb, and human mutT, were abundantly expressed in primary lung cancers (10 of 18, 15 of 18, and 6 of 12 tumors, respectively). In contrast, the presence of PGP9.5 and B-myb was much less frequent in primary tumors derived from other tissue origins. These results suggest that at least a portion of the transcripts identified by SAGE are frequently associated with lung cancer, and that their overexpression may contribute to lung tumorigenesis. The identification and further characterization of genes generated by SAGE should provide potential new targets for the diagnosis, prognosis, and therapy of lung cancer.

Bronchi↗
PubMed1998

Analysis of K-ras gene mutations in lung carcinomas: correlation with gender, histological subtypes, and clinical outcome.

PURPOSE: Lung cancer is respectively the leading and second-leading cause of cancer deaths among women and men in Taiwan. The commonest pathological type of lung carcinoma found in Taiwan is adenocarcinoma. and it has been documented that K-ras oncogene mutation occurs in a subset of lung adenocarcinoma. We therefore investigated the mutation spectrum and clinicopathological significance of K-ras oncogene mutations in lung cancer patients in Taiwan. METHODS: The lung tumors were surgically resected from 84 lung cancer patients. DNA was isolated and the mutation spectrum was examined by direct sequencing. These data were also correlated with the clinicopathological characteristics of patients. RESULTS: K-ras gene mutations were detected in 5 cases among the 84 patients investigated (6.0%). The majority of mutations occurred in exon 1 (80%, 4 of 5) and were located mainly in codons 12 and 13. Two patients had G x C --> T x A transversions and 2 patients had G x C --> A x T transitions. Notably, 1 patient had a G x C base-pair deletion from the contiguous G x C base pairs located between codons 68 and 69. All mutations occurred in male patients who were smokers. The incidences of K-ras gene mutation among male and female patients with adenocarcinoma were 13% and 0% respectively. Patients with K-ras gene mutation survived for shorter periods than those without mutations (P = 0.08, by the log-rank test). CONCLUSIONS: The incidence of K-ras gene mutations for male and female patients with adenocarcinoma was 13% and 0% respectively. Thus, the role of K-ras in the development of lung adenocarcinoma among Chinese men who are predominantly smokers is not significantly different from that in other populations worldwide. However, K-ras mutations may not be associated with adenocarcinoma among women in Taiwan, who are virtually all nonsmokers.

Adenocarcinoma↗
PubMed1998

Standardized clinical care pathways for major thoracic cases reduce hospital costs.

BACKGROUND: Standardized clinical care pathways have been developed for postoperative management in an attempt to contain costs in an era of rising health care costs and limited resources. The purpose of this study was to assess the effect of these pathways on length of stay, hospital charges, and outcome for major thoracic surgical procedures. METHODS: All anatomic lung (segmentectomy, lobectomy, and pneumonectomy) and partial and complete esophageal resections performed from July 1991 to July 1997 were retrospectively analyzed for length of stay, hospital charges, and outcome. A prospectively developed database was used. Clinical care pathways were introduced in March 1994. Comparisons were made between the procedures performed before (group I) and after (group II) pathway implementation. Common to both pathways are early mobilization and prudent x-ray and laboratory analysis. In addition, the pathway for esophagectomies emphasizes overnight intubation with 24-hour intensive care unit care, and staged diet advancement. The discharge goal was postoperative day 10. For lung resection the emphasis is early postoperative extubation with overnight intensive care unit management. The discharge goal was postoperative day 7. RESULTS: Group I esophagectomies (n = 56) had significantly greater hospital charges compared with group II (n = 96) ($21,977 +/- $13,555 versus $17,919 +/- $5,321; p < 0.04, in actual dollars) and ($29,097 +/- $18,586 versus $19,260 +/- $6,000; p < 0.001, in dollars adjusted for inflation) and greater length of stay (13.6 +/- 6.9 versus 9.5 +/- 2.8 days; p < 0.001). Group I lung resections (n = 185) had a significantly greater length of stay compared with group II (n = 241) (8.0 +/- 6.2 versus 6.4 +/- 3.8 days; p < 0.002); although charges trended downward ($13,113 +/- $10,711 versus $12,404 +/- $7,189; not significant) in actual dollars, charges were significantly less in dollars adjusted for inflation ($17,103 +/- $13,211 versus $13,432 +/- $8,056; p < 0.01). The most significant decreases in charges for esophagectomies were in miscellaneous charges (61% in dollars adjusted for inflation), pharmaceuticals (60%), laboratory (42%) and radiologic (39%) tests, physical therapy charges (35%), and routine charges (34%). For lung resections the greatest savings occurred for pharmaceuticals (38%), supplies (34%), miscellaneous charges (25%), and routine charges (22%). Mortality was similar (esophagectomies: I, 3.6%; II, 0%; lung resections: I, 0.5%; II, 0.8%; not significant). CONCLUSIONS: Introduction of standardized clinical pathways has resulted in a marked reduction of length of stay for all major thoracic surgical procedures. Total charges were reduced for both esophagectomies (34%) and lung resections (21%) with continued quality of outcome.

Aged↗
PubMed1998

Relationship of the long thoracic nerve to the scapular tip: an aid to prevention of proximal nerve injury.

OBJECTIVE: The objective was to determine the course of the long thoracic nerve relative to the scapula as an aid to the prevention of proximal long thoracic nerve injuries. METHODS: Eighteen fresh cadavers (7 male, 11 female) were studied. Each was sequentially placed in the transaxillary and posterolateral thoracotomy positions, and the distance of the long thoracic nerve from the scapular tip and anterior scapular border was measured. The measurements were made bilaterally; the mean, standard deviation, and 99% confidence interval were calculated for each position by gender. RESULTS: Distances from the scapular tip to the long thoracic nerve are listed as mean/outer range: transaxillary thoracotomy, male 4.9/7.0 cm left, 5.2/7.5 cm right; female 4.3/5.0 cm left, 4.7/6.0 cm right; posterolateral thoracotomy, male 3.1/6.0 cm left, 4.5/5.1 cm right; female 3.2/4.5 cm left, 3.8/5.5 cm right. In all instances, the long thoracic nerve was furthest from the scapula at its tip. CONCLUSION: For patients positioned for a transaxillary thoracotomy, incision sites should be at least 7.5 and 6.0 cm anterior to the scapular tip for male and female patients, respectively. For patients in posterolateral thoracotomy positioning, incisions should be 6.0 and 5.5 cm anterior to the scapular tip for male and female patients, respectively. By using these anatomic guidelines, we believe that the incidence of iatrogenic proximal long thoracic nerve injury can be minimized.

Adult↗
PubMed1998

Telomerase: a potential marker of bladder transitional cell carcinoma in bladder washes.

Telomerase is an enzyme that immortalizes cells by maintaining a constant telomere length. Here, telomerase activity in bladder washes was analyzed and compared with the final pathological diagnosis in 23 patients with bladder transitional cell carcinoma (TCC). Bladder washes and normal tissues were obtained from each patient prior to transurethral resection of bladder tumor. Telomerase activity was detected using telomeric repeat amplification protocol assay based on PCR. Cytological diagnosis of centrifuged cells from bladder washes was made using Papanicolau's stain. Results demonstrated that telomerase activity was detected in 95.7% of both cancer tissues and bladder washes. In normal tissues, telomerase activity was not detected in 22 of 23 samples. Regarding cytological diagnosis, only 69.6% of bladder wash samples had positive cytology. Moreover, in five cases of grade 1 TCC, only 20% of the cytological specimens were positive for malignancy, whereas 80% showed positive telomerase activity. These results demonstrate that telomerase activity is detectable in a majority of human bladder cancer tissues and bladder washes obtained from patients with TCC. In addition, results of this study suggest that the presence of telomerase in bladder washes may be a specific marker of bladder cancer, especially in low-grade tumors.

Aged↗
PubMed1997

Cryopreservation of kunming mouse oocytes using slow cooling, ultrarapid cooling and vitrification protocols.

The cryopreservation of oocytes has been only marginally successful with any of the current protocols, including slow cooling, rapid cooling and vitrification. We wished to test the hypothesis that oocytes from a single mouse strain would freeze successfully by 1 of the 3 mentioned protocols. Unfertilized Kunming mouse oocytes obtained 14 h after PMSG/hCG administration were randomly assigned to be cryopreserved after slow cooling, ultra rapid cooling and vitrification. Oocytes were thawed by straws being placed into 37 degrees C water, and their morphological appearance and in vitro fertilization capability were compared with that of oocytes that had not undergone cryopreservation. Survival of oocytes was indicated by the absence of darkened ooplasm or by broken membranes or zona pellucida. Functional integrity was evaluated by the formation of a 2-cell embryo after IVF. Survival rate of slow cooled oocytes did not differ from that seen in vitrified oocytes (55.1 vs 65.9%) but was significantly lower in the rapidly cooled oocytes (24.2%; P < 0.01). The results of IVF of slow cooled and vitrified oocytes were similar to those of the control group (72 and 73 vs 77%; P > 0.05). It appears that Kunming mouse oocytes can be successfully cryopreserved using the slow cooling method with 1,2-propanediol and vitrification, which contains both permeating and nonpermeating cryoprotectants.

Journal Article↗
PubMed1997

Effect of lead ingestion on concentrations of lead in tissues and eggs of laying Tsaiya ducks in Taiwan.

This experiment was conducted to investigate Pb concentrations in soft tissues and eggs from laying Tsaiya ducks (Anas platyrhynchos var. domestica), dosed via gelatin capsule with 10 or 20 mg Pb/kg BW daily for 3 mo. Body weights of ducks were not influenced by Pb treatment. In addition, no clinical syndromes involving Pb intoxication were found throughout the experiment. The two levels of Pb consistently resulted in increases in the Pb content of blood, kidney, liver, and gizzard, whereas only 20 mg Pb/kg BW per d of dose additionally increased the Pb in femoral muscle. More Pb was deposited in the kidney and liver after Pb exposure than in the gizzard or femoral muscle. Lead residues in yolk and eggshell from Pb-dosed ducks were significantly higher than in controls; however, Pb in albumen was generally low and was not influenced by Pb treatment.

Administration, Oral↗
PubMed1997

Psychosocial difficulties and emergency department use.

OBJECTIVE: To determine whether psychosocial difficulties are more prevalent among ambulatory patients using the ED for nonemergent complaints as compared with ambulatory patients having emergent complaints. METHODS: A survey of noncritical ED patients was performed using anonymous questionnaires addressing psychosocial difficulties: psychiatric illness, educational level, homelessness, alcohol and/or drug dependency (CAGE and DAST surveys), and depression (DSM-III criteria). Three independent physicians ranked each patient's chief complaint as either emergent or appropriate for primary care. The majority ranking was used to determine whether the complaint was emergent. Groups with and without specific psychosocial difficulties were compared for their proportion of emergent vs primary care complaints. RESULTS: Of 700 patients, 367 (52%) met criteria for > or = 1 psychosocial difficulty [acute psychosis-36 (5%), illiteracy-139 (20%), homelessness-45 (6%), alcohol dependency-111 (16%), drug dependency-66 (9%), and depression-130 (19%)]. There were 379 (54%) ED visits considered emergent. Patient groups with vs without > or = 1 psychosocial difficulty had similar rates of emergent visits (58% vs 50%, p = 0.04). Emergent visit rates also were similar for subgroups with vs without specific psychosocial difficulties: psychosis (56% vs 54%, p = 1.00) illiteracy (58% vs 53%, p = 0.89), homelessness (62% vs 54%, p = 0.33), alcohol dependency (62% vs 53%, p = 0.08), drug dependency (59% vs 54%, p = 0.47), or depression (58% vs 53%, p = 0.42). CONCLUSION: Psychosocial difficulties are common among ED patients; however, emergent complaints are just as common in these patients as they are in those without psychosocial difficulties.

Adult↗
PubMed1997

Elevated serum levels of mucin-associated antigen in patients with acute respiratory distress syndrome.

Increased serum levels of mucin-associated antigen have been previously demonstrated in patients with cystic fibrosis (CF) and interstitial pneumonia, and in lung-transplant recipients. The present study assessed the serum airway mucin levels in patients with acute respiratory distress syndrome (ARDS). An enzyme-linked immunosorbent assay (ELISA) method with a human-airway-mucin-specific monoclonal antibody (17Q2) was used to measure serum mucin levels in normal subjects, chronic smokers, patients with chronic bronchitis and other pulmonary diseases, patients with acute cardiogenic lung edema, and patients with ARDS. The serum mucin levels measured 9.9 +/- 0.8 ng/ml (mean +/- SEM, n = 59) in normal subjects, 12.7 +/- 1.6 ng/ml (n = 29) in chronic smokers, 21.8 +/- 1.9 ng/ml (n = 28) in patients with chronic bronchitis and other pulmonary diseases, 9.0 +/- 3.1 ng/ml (n = 5) in patients with acute cardiogenic lung edema. The serum mucin level was 53.8 +/- 6.6 ng/ml (n = 13) in patients with ARDS (p < 0.05, as compared with the four other groups). Serial measurements of serum mucin levels were obtained in patients with ARDS. Statistical analysis showed an inverse correlation of serial measurements of serum mucin with static respiratory-system compliance (p = 0.021), an inverse correlation of sequential serum mucin levels and log(Pa(O2)/Fl(O2)) (p = 0.016), and a positive correlation of sequential serum mucin levels and lung injury score (LIS) (p = 0.019). Gel-filtration analysis showed that mucin-associated antigens in ARDS sera were polydispersed and smaller than the antigens in normal sera. This study indicates that an increasing amount of degraded mucin occurs in patients with ARDS.

Acute Disease↗
PubMed1997

Selection of invasive and metastatic subpopulations from a human lung adenocarcinoma cell line.

To better understand the mechanism(s) underlying lung cancer invasion and metastasis, a Transwell invasion chamber was used to select progressively more invasive cancer cell populations from a clonal cell line of human lung adenocarcinoma, CL1. Five sublines with progressive invasiveness, designated CL1-1, CL1-2, CL1-3, CL1-4, and CL1-5, were obtained through this in vitro selection process. Their invasive abilities through basement membrane matrix showed a 4- to 6-fold increase over that of the parental cells. Moreover, the sublines manifested an increase in their colony-forming ability on soft agar, tumorigenicity, and metastatic potency in severe combined immunodeficiency (SCID) mice. Examining the phenotypes of the cell lines revealed increased expression of 92 kD gelatinase and an increase in the cell population stained with anti-keratin-8 and -18 antibodies. Clonal isolation of anti-keratin-18-antibody-positive and -negative cell populations demonstrated a correlated enhancement of the invasiveness of these cells and their expression of keratin-18. These results support the notion that the metastatic behavior of lung cancer cells can be characterized with this in vitro system, and that the properties of these progressively invasive cancer cells can be clonally studied.

Adenocarcinoma↗