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Biomedical subjects

H S Chiang

Publications and source records attributed to H S Chiang.

At least 19 recordsLinked to original sources
PubMed2005

Correlations of androgen deficiency with clinical symptoms in Taiwanese males.

The purpose of this study was to elucidate correlations between different biochemical measurements of androgen deficiency and clinical symptoms in male residents of Taiwan. An investigation of the serum biochemical markers for androgen deficiency in 650 males, including total testosterone, calculated free testosterone, and bioavailable testosterone, was conducted. Measurements of clinical symptoms were obtained using a questionnaire of the androgen deficiency in the aging male (ADAM) by St Louis University (SLQ). Correlations among the biochemical markers, correlations of the biochemical markers and age, and relationships between the biochemical markers and the SLQ were evaluated. The sensitivity and specificity of the SLQ were determined. Bioavailable and calculated free testosterone correlated better with age than did total testosterone. Eighty percent of the men had a positive SLQ, and 20% had a negative SLQ. The percentage of positive SLQ results increased with age. No statistically significant difference was noted between the biochemical markers of bioavailable and calculated free testosterone levels and the SLQ status except for men aged over 70 years. The SLQ in this study showed an acceptable sensitivity of about 80%, but the specificity was poor (about 20%). In conclusion, bioavailable testosterone and calculated free testosterone were more-closely correlated with age and may be better biochemical markers for androgen deficiency. SLQ might not be a suitable single measurement for androgen deficiency and should be used together with biochemical markers.

Adult↗
PubMed2004

Changing trends of prostate cancer in Asia.

Although Asian people have the lowest incidence and mortality rates of prostate cancer in the world, these rates have risen rapidly in the past two decades in most Asian countries. Prostate cancer has become one of the leading male cancers in some Asian countries. In 2000, the age-adjusted incidence was over 10 per 100000 men in Japan, Taiwan, Singapore, Malaysia, the Philippines and Israel. Although some of the increases may result from enhanced detection, much of the increased incidence may be associated with westernization of the lifestyle, with increasing obesity and increased consumption of fat. The differences in incidences between native Americans and Asian immigrants are getting smaller, reflecting a possible improvement of diagnostic efforts and changes of environmental risk factors in Asian immigrants. Nevertheless, the huge variations in incidences among ethnic groups imply that there are important genetic risk factors. The stage distributions of prostate cancer in Asian populations are still unfavorable compared to those of Western developed countries. However, a trend towards diagnosing cancer with more favorable prognosis is seen in most Asian countries. Both genetic and environmental risk factors responsible for elevated risks in Asian people are being identified, which may help to reduce prostate cancer incidence in a chemopreventive setting.

Asia↗
PubMed2004

Cystic fibrosis transmembrane conductance regulator gene screening and clinical correlation in Taiwanese males with congenital bilateral absence of the vas deferens.

BACKGROUND: In Taiwan, an area with a very low incidence of cystic fibrosis (CF), we first screened for the most common mutations of the cystic fibrosis transmembrane conductance regulator (CFTR) gene and looked for clinical correlations in 27 patients with clinically diagnosed congenital bilateral absence of the vas deferens (CBAVD). METHODS AND RESULTS: The clinical results showed that none of the 27 patients had CF symptoms. We did not detect any definite renal anomaly ultrasonographically. Mutation analysis was carried out on these 27 cases and 46 normal fertile males as controls. No mutations of Delta F508 or R117H were identified in any of the samples analysed. In the screening of IVS8-poly T, five of the 27 CBAVD patients showed the homozygous genotype for 5T/5T, 14 showed the heterozygous genotype for 5T/7T and eight showed the homozygous genotype for 7T/7T. The frequency of 5T alleles was 44.4%, which was significantly higher than in the 46 normal fertile males, for which there was a 5T frequency of 5.4%. CONCLUSIONS: The absence of major mutations of CFTR genes could be related to the much lower CF incidence in Taiwan. Further investigations into differences in the mutation spectrum of other CFTR genes are needed for a better understanding of the development of Taiwanese-Oriental CBAVD.

Alleles↗
PubMed2000

Complications of urinary diversion after pelvic exenteration for gynecological malignancy.

A series of 21 patients who underwent pelvic exenteration for local advanced or recurrent gynecological malignancies and urinary diversions was retrospectively reviewed. The major disease process was carcinoma of the cervix. Early complications included sepsis with wound infection and dehiscence in 4 patients, intestinal insuffency in 2 patients, 4 urinary fistulas and 3 ureteral obstructions. Six patients had a late urinary complication of stenosis of the ureterointestinal anastomosis; stones in the urinary reservoir and pyelonephritis were also noted. Factors responsible for these complications are identified and discussed with a view to reducing the morbidity related to urinary diversion in such patients.

Adult↗
PubMed2000

Genetic screening for patients with azoospermia and severe oligo-asthenospermia.

In order to explore the genetic defects of patients with azoospermia or severe oligo-asthenospermia, screening examinations were carried out for the chromosome disorder and gene deletion of the Y chromosome for 220 male infertility patients. The present results show that the total prevalence of genetic defects is 23.6%, including 38 patients (28.4%) with chromosome disorder and 14 patients (16.8%) with gene deletion in the Yq arm. The most prevalent chromosome anomaly is 47XXY (Klinefelter's syndrome), which includes 18 cases of pure type and three cases of mosaic type. Variable autosomal translocations occurred in both the azoospermia group (5.2%) and the oligo-astheno-spermia group (5.8%) with similar prevalence. A total of 22 patients had deletions of the variable, interstitial portion of the Yq arm. These gene deletions are distributed not only inside the AZF region, but also outside of this region. The severity of deletions is not well correlated to the clinical testicular function of the patients. We conclude that chromosome disorder and gene deletions are the causative factors of patients with azoospermia and oligo-asthenospermia. Genetic screening should be a routine examination for them before the use of assisted-reproductive technologies.

Adult↗
PubMed2000

10 years of experience with penile prosthesis implantation in Taiwanese patients.

PURPOSE: We evaluated the long-term results of penile prosthesis implantation during the last 10 years. Special considerations were examined concerning Asian corporeal diameter, device survival and sociocultural factors influencing patient-partner satisfaction. MATERIALS AND METHODS: We followed 331 patients who underwent penile prosthesis implantation from December 1985 to May 1996. Surgical data, postoperative complications and information from a survey on satisfaction are reported. RESULTS: The most prevalent corporeal diameter in our patients was 11.0 to 11.5 cm. Postoperatively wound infection was the most serious surgical complication. The 5-year device survival was similar in the malleable and inflatable types except for a poorer outcome with the self-contained inflatable Hydroflex penile prosthesis. Overall patient satisfaction with surgery was 86.6%. CONCLUSIONS: Penile prosthesis implantation still has its place as definitive therapy in some patients with uncorrectable erectile dysfunction. In Taiwanese society more consideration of prosthesis selection, surgical preparation and patient-partner counseling is the basis for further success in the future.

Actuarial Analysis↗
PubMed2000

Titration study of MUSE (Medicated Urethral System for Erection) in erectile dysfunction.

PURPOSE: We assessed the erectile responses and adverse reactions to prostaglandin E1 delivered via the medicated urethral system for erection (MUSE) in a titration study to determine optimal dose. METHODS: Sixty-four patients with erectile dysfunction underwent in-office testing with MUSE to determine erectile response. Following thorough instructions, patients were taught how to use MUSE themselves. The titration study started with a dose of 125 micrograms, and increased to 250 micrograms, 500 micrograms, and finally 1,000 micrograms. In patients who had an erectile response, erection scoring, color duplex Doppler study, blood pressure monitoring, recording of subjective complaints, and repeated laboratory examinations were performed to evaluate the positive and adverse effects of MUSE. RESULTS: Forty-three of the 64 patients achieved a maximal erection with MUSE, as shown by systolic peak flow velocities in the deep penile arteries of greater than 27 cm/s on Doppler ultrasonography. One patient was unsatisfied with his erectile response and dropped out of the study. Of the 42 patients who completed the study, most (35) were satisfied with the response achieved at the higher doses of 500 micrograms and 1,000 micrograms. A modified soft rubber band was needed to achieve a satisfactory erectile response in 18 patients. Only four patients experienced serious urethral burning during MUSE application. CONCLUSIONS: MUSE was effective and safe in most patients with erectile dysfunction in this study. For patients not satisfied with the extent of penile rigidity achieved with MUSE, the use of a modified soft rubber band for erectile assistance, as well as a program for improved patient education, may help to achieve a better erectile response and facilitate compliance with treatment regimens at home.

Adult↗
PubMed1999

The percutaneous penetration of prostaglandin E1 and its alkyl esters.

The percutaneous delivery of PGE1 and its alkyl esters in alcoholic saline solution through hairless mouse skin was compared. The quantification of alkyl esters was based on the same principle as that for PGE1, which was converted to PGB1 to enhance the sensitivity and minimize the interference. Results showed that it was PGE1 that appeared in the receiver compartment for all alkyl esters examined. The flux of all alkyl esters of PGE1 in the same concentration was higher than PGE1 itself at most of saline vehicle with various fractions of alcohol. The maximal flux for a fixed concentration of each alkyl ester appeared at different fractions of alcohol. When the fractions of alcohol was kept constant, the alkyl ester that showed the maximal flux at this concentration appeared to have a longer chain length with increasing the fraction of alcohol. But isopropyl ester deviated from this order. It was concluded that the alkyl ester derivatives promoted the penetration of PGE1 mainly as a result of enhancing the drug partitioning into the stratum corneum. The alcohol fraction that needed to achieve the maximal flux at the same concentration increased with the increase of alkyl chain length, which resulted in the decrease of solubility parameter. It is necessary to optimize the fraction of alcohol in the saline solution in order to achieve the maximal flux at a fixed concentration for these alkyl esters with different alkyl chain length.

Alprostadil↗
PubMed1998

Investigation of the percutaneous penetration of prostaglandin E1 and its ethyl ester.

The optimization of percutaneous delivery of PGE1 and its ethyl ester in alcoholic buffer solution through hairless mouse skin was investigated. A reversed-phase HPLC system with a photodiode array detector was used to differentiate the UV spectra of the penetration products. By comparison of the UV spectrum for each chromatographic peak, the conversion of PGE1 ethyl ester to PGE1 by enzymatic hydrolysis was found to be the predominant degradation pathway during the in vitro penetration. The quantification of ethyl ester was developed based on the same principle as that for PGE1. It was then applied to monitor the penetration of prostaglandins through hairless mouse skin from the vehicles containing various fractions of alcohol. Results demonstrated that the alkyl group promoted the penetration mainly as a result of enhancing the drug partitioning into the stratum corneum at its maximal thermodynamic activity. The alcohol fraction around 20% seemed to be optimal for the percutaneous delivery of the ethyl ester. The use of collagen gel to carry PGE1 ethyl ester for percutaneous application was included for comparison. The effect of adding alcohol in the collagen gel on the penetration of PGE1 ethyl ester was found to be slightly lower than that from the same vehicle without collagen.

Alprostadil↗
PubMed1998

Tissue factor activity of SW-480 human colon adenocarcinoma cells is modulated by thrombin and protein kinase C activation.

Expression of tissue factor (TF), a cellular initiator of the extrinsic coagulation cascade, is a feature of many malignant tumours and is intimately involved in the process of metastasis. SW-480 human colon adenocarcinoma cells responded to thrombin (1 U ml(-1)) or phorbol 12-myristate 13-acetate (PMA, 0.1 microM) with a 6.0-fold and a 7.7-fold increase in their procoagulant activity (PCA), respectively, after 4-6 h incubation in serum-free medium. The thrombin-enhanced PCA was significantly inhibited by complexing of thrombin with hirudin, or by serine protease inhibition with 3,4-dichloroisocoumarin. Both effects of thrombin and PMA on PCA in SW-480 cells were blocked by pretreatment of cells with cycloheximide or actinomycin D, indicating that the response required de novo protein and RNA synthesis. The thrombin-enhanced PCA depended on the activation of protein kinase C (PKC) as it was diminished by staurosporine and calphostin C. Moreover, stimulation of SW-480 cells by thrombin or PMA led to a significant increase in TF mRNA within 3 h as measured by the reverse-transcription PCR method, which was also dependent on the activation of PKC. The unaltered decay rate of thrombin-enhanced TF mRNA, evaluated after the addition of staurosporine, suggested that its inhibitory effect occurred at a transcription level. Our data suggest that thrombin enhances TF gene expression and protein synthesis in tumour cells in vitro via PKC activation. The induction of TF expression in tumour cells by thrombin indicates that tumour-associated PCA might have a positive-feedback effect on in vivo local propagation of thrombus by thrombin formation.

Adenocarcinoma↗
PubMed1998

Surgical and pathologic observations of epididymal tubules during microscopic epididymal sperm aspiration for intracytoplasmic sperm injection.

Microscopic epididymal sperm aspiration (MESA) for sperm retrieval and intracytoplasmic sperm injection (ICSI) is currently our routine treatment for selected male patients with obstructive azoospermia. In order to refine the surgical technique and obtain better quality sperm for our assisted reproductive technology program, we observed the epididymal tubules in 40 sessions of surgical exploration of the epididymis for sperm aspiration. Epididymal tubules with long-term obstruction could be divided into three groups on the basis of clinical observations and pathology findings: markedly dilated, mildly dilated, and nondilated. All of the markedly dilated epididymal tubules (grade III, n = 10) were azoospermic and ICSI could not be done. Epididymal sperm obtained from the mildly dilated tubules (grade II, n = 9) resulted in poorer fertilization (49%) and pregnancy (33%) rates than sperm obtained from nondilated epididymal tubules (grade I, n = 21, fertilization rate 72%, pregnancy rate 57%). These findings demonstrate that nondilated epididymal tubules are best for sperm retrieval and successful ICSI. We believe this observation will be a good surgical parameter for urologic surgeons performing MESA.

Epididymis↗
PubMed1997

Arsenic in drinking water and incidence of urinary cancers.

The associations between arsenic ingestion and cancers of the bladder and kidney have been documented in Taiwan. To evaluate further such associations for urinary cancers of various cell types, we conducted an ecologic study encompassing 243 townships using cancer registry data of patients diagnosed between 1980 and 1987. We used the proportions of wells with various specified arsenic levels in each township as indicators of exposure and evaluated the effects of urbanization and smoking by an urbanization index and the number of cigarettes sold per capita. In both genders, we observed associations of high arsenic levels in drinking water with transitional cell carcinomas of the bladder, kidney, and ureter and all urethral cancers combined. We also observed such associations in adenocarcinomas of the bladder in males, but not in squamous cell carcinomas of the bladder or renal cell carcinomas or nephroblastomas of the kidney. There was also a positive association between the urbanization index and transitional cell carcinomas of the ureter in males. The number of cigarettes sold per capita was not a good predictor for urinary cancers. The results indicate that the carcinogenicity of arsenic may be cell type specific.

Adolescent↗
PubMed1996

Characterisation of platelet aggregation induced by PC-3 human prostate adenocarcinoma cells and inhibited by venom peptides, trigramin and rhodostomin.

PC-3 cells, a metastatic human prostate adenocarcinoma line, caused dose-dependent platelet aggregation in heparinised human platelet-rich plasma (PRP). PC-3 tumour cell-induced platelet aggregation (TCIPA) was completely inhibited by hirudin (5 U/ml) and limited by increasing concentrations of apyrase. This TCIPA was unaffected by cysteine proteinase inhibition with E-64 (10 microM), but was limited by cell pretreatment with phospholipase A2. PC-3 cell suspension caused marked, dose-dependent decreases in plasma recalcification times using normal, Factor VIII-deficient and Factor IX-deficient, but not Factor VII-deficient, human plasma. This effect was potentiated in cell lysates, but was inhibited in intact cells preincubated with sphingosine. Overall, these data suggest that PC-3 TCIPA arises from PC-3 tissue factor activity expression. Trigramin and rhodostomin, RGD-containing snake venom peptides which antagonise the binding of fibrinogen to platelet membrane glycoprotein IIb-IIIa, prevented PC-3 TCIPA. Similarly, synthetic peptide GRGDS as well as monoclonal antibodies against platelet membrane glycoproteins IIb-IIIa and Ib prevented PC-3 TCIPA, which was unaffected by control peptide GRGDS. On a molar basis, trigramin (IC50, 0.11 microM) and rhodostomin (IC50, 0.03 microM) were approximately 5000 and 18000 times, respectively, more potent than GRGDS (IC50, 0.56 mM).

Adenocarcinoma↗
PubMed1996

Thrombin enhances the adhesion and migration of human colon adenocarcinoma cells via increased beta 3-integrin expression on the tumour cell surface and their inhibition by the snake venom peptide, rhodostomin.

The interactions between tumour cells and the microvasculature, including the adhesion of tumour cells to endothelium and extracellular matrix (ECM) as well as their migratory ability, are prerequisites for metastasis to occur. In this study we showed that thrombin is capable of enhancing in vitro tumour cell metastatic potential in terms of adhesive properties and migratory response. Following exposure to subclotting concentrations of thrombin, SW-480 human colon adenocarcinoma cells exhibited increased adhesion to both the endothelium and ECM component (i.e. fibronectin). Likewise, the pretreatment of thrombin enhanced the migratory ability of SW-480 cells. The enhanced adhesion was significantly inhibited by complexing of thrombin with its inhibitor hirudin, or by serine proteinase inhibition with 3,4-DCI, but was unaffected by pretreatment of tumour cells with actinomycin D or cycloheximide. The effect of thrombin resulted in an upregulated cell-surface expression of beta 3 integrins, a group of receptors mediating interactions between tumour cells and endothelial cells, and between tumour cells and ECM. Antibodies against beta 3 integrins effectively blocked both the enhanced adhesion and migration. This thrombin-mediated up-regulation of beta 3 integrins involved the activation of protein kinase C (PKC) as thrombin-enhanced adhesion was diminished by PKC inhibition. Rhodostomin, an Arg-Gly-Asp-containing antiplatelet snake venom peptide that antagonises the binding of ECM toward beta 3 integrins on SW-480 cells, was about 600 and 500 times, more potent that RGDS in inhibiting thrombin-enhanced adhesion and migration respectively. Our data suggest that PKC inhibitors as well as rhodostomin may serve as inhibitory agents in the prevention of thrombin-enhanced metastasis.

Adenocarcinoma↗
PubMed1996

Pregnancy following in vitro fertilization and embryo transfer by microsurgical epididymal sperm aspiration from a patient with congenital absence of the vas deferens: a case report.

Congenital absence of the vas deferens (CAVD) has been considered a virtually untreatable cause of male infertility. Men with this condition have been shown on testicular biopsy to have adequate spermatogenesis, and are theoretically producing sperm capable of fertilizing an oocyte. Yet epididymal transit was thought to be essential for the maturation of spermatozoa and development of their fertilizing ability since the characteristics of sperm motility improve as the sperm passes through the cauda. However recent studies in man have shown that spermatozoa aspirated from the obstructed caput epididymis and ductuli efferentia are, in fact, capable of fertilization in vitro. Microsurgical epididymal sperm aspiration (MESA) from the proximal region (caput) of the epididymis, obtained 0.5 x 10(6) sperm per ml, following washing and direct swim-up. Twelve oocytes were inseminated and three embryos were generated for transfer. The patient conceived and delivered a healthy female baby weighting 2838 gm, on March 3, 1994. This is the first documentation in Taiwan of live birth resulting from MESA from a patient with CAVD combined with in vitro fertilization and embryo transfer.

Adult↗
PubMed1996

Clinical study of vasectomy reversal: results of 60 single-surgeon cases in Taiwan.

During a 10-year period, 60 men who had undergone vasectomy reversal were studied at Taipei Medical College Hospital. The age range of the patients was 28 to 67 years (average, 41.9 +/- 6.9 yr). Vasectomy had been performed between 3 months and 35 years previously (average, 8.6 +/- 6.1 yr). The most common reason for requesting a vasovasostomy was the desire to have children with a new partner (68.3%). However, psychological symptoms (16.7%) and the desire to have a boy (11.7%) were also prominent findings in this study. Of 38 men who had postoperative semen analyses, sperm was present in the semen in 32 (84.2%), and pregnancy occurred in 14 of 38 couples (36.8%) within the first year of follow-up. Repeat microsurgical reversal procedures were also promising, and of a total of eight patients who had repeat surgery, patency was established in five patients (62.5%).

Adult↗
PubMed1995

Characterization of platelet aggregation induced by human breast carcinoma and its inhibition by snake venom peptides, trigramin and rhodostomin.

MCF-7 cells, a metastatic human breast carcinoma line, caused dose-dependent platelet aggregation in heparinized human platelet-rich plasma (PRP). MCF-7 tumor cell-induced platelet aggregation (TCIPA) was almost blocked by apyrase (0.5 U/ml) and completely inhibited by hirudin (5 U/ml). This TCIPA was unaffected by cysteine proteinase inhibition with E-64 (10 microM), but was limited by cell pretreatment with phospholipase A2. MCF-7 cell suspension caused marked, dose-dependent decrease in plasma recalcification times using normal, Factor VIII-deficient, and Factor IX-deficient human plasma. This effect was potentiated in cell lysates but was inhibited in intact cells preincubated with sphingosine. MCF-7 cell suspension did not affect the recalcification time of Factor VII-deficient plasma. Taken together, these data suggest that MCF-7 TCIPA arises from MCF-7 tissue factor activity expression. Trigramim and rhodostomin, RGD-containing snake venom peptides which antagonized the binding of fibrinogen to platelet membrane glycoprotein IIb/IIIa, prevented MCF-7 TCIPA. Likewise, synthetic peptide GRGDS as well as monoclonal antibodies against human tissue factor, platelet membrane glycoprotein IIb/IIIa and Ib prevented MCF-7 TCIPA, which was unaffected by control peptide GRGES. On a molar basis, trigramin (IC50, 0.1 microM) and rhodostomin (IC50, 0.03 microM), were about 5,000 and 18,000 times, respectively, more potent than GRGDS (IC50, 0.54 mM).

Adenocarcinoma↗