Biomedical subjects
Publications and source records attributed to S C Yang.
We describe a case of pericardial tamponade as an initial manifestation of systemic lupus erythematosus (SLE). Although pericarditis or pericardial effusion is the common cardiac complication of SLE, tamponade is unusual. Treatment consists of pericardiocentesis, administration of high dose glucocorticoid an antimalarial drug.
The enzyme telomerase maintains a constant telomere length in immortalized cells, allowing unlimited cell proliferation. Almost all cancer cells express telomerase activity. However, little data is available regarding the role of telomerase activity in the detection of bladder cancer with a bladder wash specimen. We detected telomerase activity in a bladder wash specimen of bladder cancer and normal tissues, and compared them with final pathologic diagnosis. Twenty-three patients with transitional cell carcinoma (TCC) of the bladder were enrolled in our study. A bladder wash specimen was obtained before transurethral resection of the bladder (TURB) and normal and cancer tissues from the same patients during TURB. Telomerase activity was analyzed in each specimen a using telomeric repeat amplification protocol (TRAP) assay based on polymerase chain reaction (PCR) technique. Cytologic diagnosis was performed using Papanicolaou's stain with cytocentrifuged cytology preparation. We observed telomerase activity in 95.7% (22/23) of bath cancer tissues and bladder wash specimens; only one case did not express telomerase activity. Telomerase activity was undetected in all normal tissues except one, which was obtained from a patient with carcinoma in situ. A total of 69.6% (16/23) of wash specimens were positive in cytopathologic diagnosis. The accuracy of cytopathologic diagnosis in pathologic grade 2 or 3 was relatively high (83.3%, 15/18). However, in five cases of grade 1 TCC only 20% (1/5) of cytologic diagnosis was positive whereas the telomerase activity of wash specimens was detected in 80% (4/5). Our data demonstrates that not only the majority of human bladder cancer tissues, but also the bladder wash specimens obtained from patients with TCC, expressed telomerase activity. It indicates that telomerase activity may be a reliable marker in detecting bladder cancer especially in cases with a low grade that bladder wash cytology can miss.
Among the nine ellagitannins, rugosin E was the most potent platelet aggregating agent with an EC50 of 1.5 +/- 0.1 microM in rabbit platelets and 3.2 +/- 0.1 microM in human platelets. The aggregations caused by rugosin E and ADP were inhibited by EGTA, PGE1, mepacrine, sodium nitroprusside and neomycin, but not by indomethacin, verapamil, TMB-8, BN52021 and GR32191B. Rugosin E-induced thromboxane formation was suppressed by indomethacin, EGTA, PGE1, verapamil, mepacrine, TMB-8 and neomycin. ADP-scavenging agents, such as CP/CPK and apyrase inhibited concentration-dependently ADP (20 microM)-, but not rugosin E (5 microM)-induced platelet aggregation. In thrombin (0.1 U/ml)-treated and degranulated platelets, rugosin E and ADP still caused 63.5 +/- 3.0% and 61.2 +/- 3.5% of platelet aggregation, respectively. Selective ADP receptor antagonists, ATP and FSBA inhibited rugosin E- and ADP-induced platelet aggregations in a concentration-dependent manner. Both rugosin E and ADP did not induce platelet aggregation in ADP (1 mM)-desensitized platelets. In contrast to ADP, rugosin E did not decrease cAMP formation in washed rabbit platelets. Both rugosin E and ADP did not cause phosphoinositide breakdown in [3H]myo-inositol-labeled rabbit platelets. In fura-2/AM-load platelets, both rugosin E and ADP induced increase in intracellular calcium concentration and these responses were inhibited by ATP and PGE1. All these data suggest that rugosin E may be an ADP receptor agonist in rabbit platelets.
Novel oncogene mutation detection techniques have demonstrated that standard histopathological examination may fail to detect clinically significant metastatic cancer cells. Recently, telomerase activity has been detected in most immortal cell lines and human tumors, potentially providing a novel diagnostic marker. We compared standard histopathological examination with the telomeric repeat amplification protocol assay and either a p53 plaque hybridization or a K-ras mutation ligation assay in the lymph nodes of 12 patents with surgically resectable non-small cell lung cancer. Telomerase activity was detected in 10 of 10 (100%) evaluable tumors. Eight of 9 (89%) histopathologically positive lymph nodes were telomerase positive, and 26 of 48 (54%) histopathologically negative lymph nodes were telomerase positive. In comparison, oligonucleotide plaque hybridization detected metastases in all 3 histopathologically positive nodes and in 3 of 27 histopathologically negative nodes. Similarly, the K-ras mutation ligation assay detected metastases in all 6 histopathologically positive lymph nodes examined and in 1 of 21 histopathologically negative lymph nodes. Thus, most of the "positive" nodes by telomerase assay did not harbor occult neoplastic cells that shared the same genetic alteration as the primary tumor. The high rate of false positives associated with the telomeric repeat amplification protocol assay limits its role in staging lymph nodes in patients with non-small cell lung cancer.
A reversed-phase high-performance liquid chromatographic method for the determination of benflumetol in human plasma is described. Benflumetol in plasma samples was extracted with a glacial acetic acid-ethyl acetate (1:100, v/v) mixture at pH 4.0. Chromatography was performed on a Spherisorb C18 column using a methanol-water-glacial acetic acid-diethyl amine (93:6:1:0.03, v/v) mixture as the mobile phase and UV-VIS detection at 335 nm. The identity and purity of the benflumetol peak were carefully examined, and the internal standard method was applied for its quantitation. The absolute recovery of benflumetol in spiked plasma samples was 92.91% over the concentration range 5-4000 ng/ml. The recovery of internal standard "8212" at a concentration of 300 ng/ml in spiked plasma was 84.85%. The detection limit of benflumetol was 11.8 ng/ml. Plasma concentration-time profiles in healthy volunteer adults were measured after a single-dose oral administration of 500 mg of benflumetol. The assay procedures were within the quality control limits.
This study was conducted to assess the CO2-elimination efficiency of tracheal gas insufflation (TGI) in 20 patients with acute respiratory distress syndrome and to compare its efficacy during volume-controlled (VCV) and pressure-controlled ventilation (PCV). TGI was initially applied as an adjunct to VCV, with continuous flows (Vcath) of 4 and 6 L/min delivered through a catheter positioned 2 cm above the carina. Total effective tidal volume (VTeff) was held constant. The percent reductions in PaCO2 (% delta PaCO2) were 13.3 +/- 2.1 and 16.7 +/- 2.7% at Vcath 4 and 6 L/min, respectively, which correlated well with the percent reduction in the end-tidal PCO2 from baseline (% delta PETCO2) (r = 0.75, p < 0.001). An inverse relationship (r = -0.65, p < 0.001 and r = -0.59, p < 0.01 at Vcath 4 and 6 L/min, respectively) was found between the % delta PaCO2 and the baseline ratio of artery to PETCO2 difference to PaCO2, which was determined as the fraction of alveolar dead space (VDalv) relative to total alveolar ventilation. Twelve patients were subsequently switched to PCV combined with Vcath 6 L/min, which provided a % delta PaCO2 of 16.1 +/- 3.0% (p = NS versus 17.1 +/- 2.6% during VCV). These data suggest that in patients with ARDS the change in PETCO2 may be helpful in predicting the decrement in PaCO2 during TGI, and the existence of a high VDalv tends to limit its effectiveness. Further, the efficacy of TGI with VCV is equivalent to that with PCV.
The presence of facial nerve paralysis in the presence of an ipsilateral parotid gland tumor is almost an indication of parotid gland malignancy. Benign parotid gland tumor with facial nerve palsy is very rare. Only three cases have been reported in the literature. The case presented here is a 40 year-old male who had had a right-side parotid tumor for three years, developing a right side facial nerve paralysis within the past three months. After surgical removal of the tumor, the facial nerve function returned to normal. The tumor was a benign tumor, as confirmed by pathological examination.
To overcome problems with conventional plastic endoprostheses, a study was conducted to determine the clinical efficacy of self-expandable metallic stents in the palliative treatment of malignant biliary obstruction. From May 1994 to March 1995, 19 self-expandable metallic stents were implanted in 13 consecutive patients with malignant obstructive jaundice due to cholangiocarcinoma (four patients), ampullary carcinoma (six), pancreatic carcinoma (one), and hepatic hilar lymph node metastasis (two). All patients underwent percutaneous transhepatic biliary drainage followed by stent insertion, except for two patients where the T-tube tract was used as access and another with previous placement of a polyethylene internal-external drainage catheter for more than 6 months. When both lobes of the biliary system were to be drained, stents were placed either side by side through punctured, separate hepatic ducts or, using a T configuration, through a single transhepatic tract. Percutaneous transhepatic stent placement was technically successful in all patients. After a mean follow-up of 5.9 months (range, 1-10 mo), 10 of 13 patients were still alive while three had died of nonprocedure-related causes. In 10 patients, total serum bilirubin levels decreased significantly (from 136.8 +/- 157 mumol/L to 34.2 +/- 22.2 mumol/L), while it increased in three patients. Two patients had stent occlusions at 2 and 3 months after stent placement, which required intervention. The overall patency period ranged from 1 to 9 months (mean, 5.1 mo). Our results confirm that the use of metallic stents is effective in the palliative treatment of malignant jaundice.
The prevalence of hepatitis C virus (HCV) infection in chronic hemodialysis patients ranges from 20 to 50% and these patients may serve as a reservoir of infection for their household contacts. The aim of this study was to investigate the prevalence of anti-HCV in hemodialysis patients and their families, and to evaluate possible routes of infection. One hundred eighty-six family members of 84 hemodialysis patients and 529 healthy adults were enrolled. The family members consisted of 50 spouses, 96 children, 11 parents, 29 siblings, and other relatives living together with the patients. Serum samples were collected for testing anti-HCV. Exposure to risk factors was obtained by a questionnaire and an interview. The results showed that prevalence of anti-HCV in hemodialysis patients was 44%, whereas in family members it was 5.4%, not significantly different from that of age-matched healthy adults (standardized morbidity rate = 1.51, P = 0.390). The anti-HCV rate in family members tended to increase with age, and a spouse of an infected hemodialysis patient had a higher risk of HCV infection than other family members (15% vs. 2.6%, odds ratio 6.6, P = 0.058). Except for the age factor, no difference was found between seropositive and seronegative family members with respect to risk factors such as blood transfusion, surgery, frequent injections, dental procedures, or acupuncture. It was concluded that, although the anti-HCV positivity of hemodialysis patients is high, the risk of HCV infection for their family members is not higher than that of the general population. Among family members, spouses of seropositive hemodialysis patients have the highest risk of HCV infection.(ABSTRACT TRUNCATED AT 250 WORDS)
SETTING: Longitudinal epidemiological study based on diabetic and non-diabetic civil servants in Korea. OBJECTIVE: To determine a comparative incidence of pulmonary tuberculosis (PTB) between diabetic and non-diabetic subjects. DESIGN: Investigation of newly developed PTB among diabetics and non-diabetics between 1988 and 1990, on the basis of biennial medical examination and the medical records of those who claimed health insurance for tuberculosis. RESULTS: The 1990 medical examination and investigation of medical records of the health insurance claimants revealed that PTB had developed in 170 patients (including 37 smear and eight culture positives) among 8015 diabetics, and in 4935 patients (including 538 smear and 342 culture positives) among 806,698 control subjects. Estimated annual incidence rates of PTB of (1) all types, (2) smear and/or culture positive versus (3) smear positive cases were 1061, 281 and 231 per 10(5) respectively among diabetics and 306, 55 and 33 per 10(5) among non-diabetic controls. PTB developed in 167 of 7695 male diabetics and in 3 of 320 female diabetics. The greater the age, the more diabetics were found. CONCLUSION: Relative risks (RR) of developing PTB of all types and bacteriologically confirmed cases were 3.47 times and 5.15 times higher in the diabetics than in the matched controls. A greater RR was observed on those at the age of 30-49 than in those of 50 years or more.
SETTING: Longitudinal epidemiological study based on civil servants in Korea. OBJECTIVE: To estimate the incidence of pulmonary tuberculosis (PTB) for the general population from a reliable sample. DESIGN: New active PTB developing between 1988 and 1990 in civil servants has been determined from (1) the findings of biennial medical examinations and (2) perusal of the medical records of those claiming health insurance for tuberculosis (TB). RESULTS: A total of 790,204 subjects was available for investigation. Active PTB was diagnosed in 5107 patients over the 2 years of the study. Bacteriological examination of 3847 patients yielded 575 (14.9%) positive smears and 350 (9.1%) smear-negative positive cultures from them. Applying these rates to the 1260 whose sputum was not examined, 702 were smear-positive, and 431 were culture-positive. Overall PTB incidence was 393 per 10(5), with 84 and 53 per 10(5) smear- and culture-positive. Incidence was high in males, and in the age group 20-29 years in both sexes. CONCLUSION: Such high PTB incidence, particularly in the age group 20-29, clearly indicates that TB in Korea remains a serious health problem.
Seventy-nine patients of bladder neck suspension using an extraperitoneal variation of laparoscopic surgery were performed for the treatment of stress urinary incontinence. Using a balloon dissector the anterior vesical pelvic space is secured. The bladder neck suspension similar to the Burch operation was performed through a laparoscopic procedure. Symptoms of patients were assessed preoperatively and at one and six months following surgery. Operative times and complications were also evaluated. Success rate was 89.8% at six months. Complications such as bladder perforations were observed. Laparoscopic extraperitoneal bladder neck suspension-(LEBNS) is a viable option to the conventional methods of suspension, it has definite cosmetic advantages, is devoid of intraperitoneal dissection and adhesion, and has a comparable success rate.
In a variation of laparoscopic surgery we performed retroperitoneal surgery using endoscopy and a special retractor in 3 cases of live donor nephrectomy. The procedure using retroperitoneal endoscopy offers several advantages compared to conventional live donor nephrectomy. With the development of retractors to obtain operating space and the further development of surgical techniques retroperitoneal endoscopic live donor nephrectomy can be established as an alternative surgical method for harvesting donated kidneys.
The hemizona assay (HZA) in Rhesus monkeys was employed to study the correlation of zona-binding ability with sperm motility or with naturally developing oocytes at various maturational stages. Oocytes from unstimulated ovaries were retrieved within 2 hr from monkeys sacrificed for vaccine production (in reproductive season, but with their menstrual cycles not determined). Oocytes were divided into four groups based on their morphological maturation: 1) Oocytes surrounded by more than one cumulus layer (MC); 2) Oocytes retaining intact germinal vesicle nuclei (GV); 3) Oocytes with germinal vesicle breakdown showing distinct perivitelline space (PVS); and 4) Oocytes extruding the first polar body (PB1). The mean numbers of sperm bound to hemizona for PB1, PVS, GV, and MC groups were 132.9 +/- 12.0, 71.5 +/- 10.1, 36.1 +/- 4.0, and 20.1 +/- 2.9 (Mean +/- SE), respectively. The four groups showed significant differences from each other in sperm/egg binding ability (P < 0.01). The number of bound sperm significantly increased with oocyte maturation. The present study also showed that zona-binding ability was also affected by sperm motility. For sperm with 67.7% motility and sperm with 31.2% motility, the average numbers of bound sperm were 43.5 +/- 2.2 and 25.3 +/- 2.9 (Mean +/- SE), respectively. There was significantly higher binding ability for sperm with higher motility (P < 0.01). The results suggest that: 1) The rhesus monkey model can serve as a very sensitive model for studying sperm/egg interaction by HZA; 2) Sperm motility positively correlated with sperm/egg binding; and 3) Sperm/egg binding ability increases with oocyte maturation.(ABSTRACT TRUNCATED AT 250 WORDS)
Diabetic rats are known to have an increased susceptibility to dental caries and major alterations in parotid salivary composition. Salivary proteins play an important part in oral health maintenance; thus specific changes in salivary protein composition in diabetic animals might alter the ecological balance in favour of cariogenic bacteria, and toward the initiation and progression of the disease process. The ability of whole, parotid and submandibular salivas from control and streptozotocin-diabetic rats to mediate the aggregation and adherence to hydroxyapatite of mutans streptococci was examined. Salivary-mediated bacterial aggregating activity was significantly reduced in whole and parotid salivas from diabetic rats, but bacterial adherence to hydroxyapatite was unaffected. The aggregating and adherence activities of rat whole saliva were derived mainly from parotid saliva, which contains predominantly low molecular-weight proteins and glycoproteins (< 200 kDa), but rat parotid saliva was capable of interacting with the bacterial receptor for the high molecular-weight aggregating factor in human saliva. SDS-PAGE of parotid saliva revealed that a number of proteins, including the basic and acid proline-rich proteins, were altered in the salivas of diabetic animals. After incubation with either Streptococcus mutans or hydroxyapatite several protein bands were depleted, and thus a variety of proteins and glycoproteins may be responsible for the adherence and aggregating activity of rat parotid saliva.
To investigate which specific kinds of base changes are induced by psoralen adducts in the genomic DNA of diploid human fibroblasts, cells were exposed to 8-methoxypsoralen (8-MOP) at 2-12 microM followed by one dose of UVA (365 nm) irradiation (PUVA-I treatment) or two doses of UVA (PUVA-II treatment). While PUVA-I treatment produced little effect on the induction of cytotoxicity, PUVA-II treatment significantly reduced the fibroblasts' colony-forming ability and resulted in about 10-fold increases in mutation frequency at the D0 dose. Mutations in the hypoxanthine (guanine) phosphoribosyltransferase (hprt) gene of 36 independent PUVA-II mutants were characterized by direct sequencing of cDNA amplified by the polymerase chain reaction (PCR). Seventeen mutants contained single base substitutions and the other 19 mutants either lacked one or more exons, or had deleted or gained nucleotides in the exon boundaries in their cDNA. The intron--exon boundaries of 10 of these 19 putative splicing mutants were further characterized by direct sequencing of the PCR-amplified hprt gene. The results showed that nine contained single base substitutions at the consensus splicing donor and acceptor sites. One splicing mutant possessed two base substitutions located at exon 8, whereas its splicing sites were intact. Most of the base substitutions occurred at T-A base pairs (24/29). The majority of T.A changes occurred at thymine of 5'TA and 5'ATA on the non-transcribed strand. Four of the five G.C base substitutions were located at guanines of 5'TG sites adjacent 3' to AT or TA sequences. In addition, the occurrence of a specific type of mutation was highly correlated to the 5' flanking bases of TA sites. The mutagenesis of 13 of the 16 mutational events at 5'TA sites on the non-transcribed strand can be explained by the preferential incisions of the photoadducts on the transcribed strand followed by misalignment--realignment during translesion repair synthesis of the bulky lesions on the non-transcribed strand.
Whether nebulized ipratropium bromide is of benefit to mechanically ventilated patients with chronic bronchitis is not well defined. The objective of the study was to determine the effect of ipratropium bromide as a nebulized solution on ventilatory function in patients with severe airflow limitation and under ventilator treatment because of respiratory failure. The design was a randomized, double-blind, controlled trial. Forty-two ventilated patients (43 to 83 years old) with acute airflow obstruction and wheezing or coughing were chosen. The patients were randomly allocated to treatment every 6 h with either 500 micrograms of nebulized ipratropium bromide or 0.9 percent saline solution. Comparison was made between ipratropium bromide and placebo. Their responses were assessed in terms of arterial blood gas analysis, pulmonary mechanics, and respiratory symptoms. No significant differences in oxygenation, arterial CO2 tension, or static lung compliance attributable to ipratropium were found. However, a significant tendency to decreased mean airway resistance, peak inspiratory pressure, mean airway pressure, and improved symptom status 24 h after giving ipratropium was observed. We conclude that ventilated patients with obstructive lung disease could obtain incremental benefit from adding nebulized ipratropium to aminophylline. Their responses may be explained by the bronchodilating effect of ipratropium that resulted in a reduced airway resistance and a lower mean airway pressure.
Our previous experiments have shown that the appetite or preference for alcohol is affected by the rat strain and nutritional status, such as dietary protein levels. To determine the affected factors in alcohol preference, the alcohol metabolism in SHRSP (stroke-prone spontaneously hypertensive rats) and WKY (Wistar-Kyoto) rats fed with the standard level (15%) or low level (5%) purified egg protein diet (PEP) was investigated. The animals were kept on the experimental diets for 4 weeks. After 12 h fasting, a 15% ethanol solution was given in a dose of 100 mg ethanol per 100 g body weight with a gastric probe to all animals and the blood ethanol and acetaldehyde levels were determined. Compared with 15% PEP diet-fed SHRSP, WKY showed higher levels of blood ethanol and acetaldehyde. Furthermore, the same results were also observed in SHRSP and WKY fed with 5% PEP diet. On the other hand, regardless of the rat strain, rats fed a low level protein diet showed higher blood ethanol and acetaldehyde levels. We also found that there was no significant change in alcohol dehydrogenase (ADH) activity and acetaldehyde dehydrogenase (ALDH) activity between SHRSP and WKY. However, both SHRSP and WKY fed a 15% PEP diet showed higher ADH and ALDH activity compared with rats fed the 5% PEP diet. These results suggested that the affected factors of preference for alcohol may be correlated with blood ethanol and acetaldehyde levels after alcohol intake.