Biomedical subjects

Yung-Ming Lin

Publications and source records attributed to Yung-Ming Lin.

13 recordsLinked to original sources

PubMed2006

Identification of ten novel genes involved in human spermatogenesis by microarray analysis of testicular tissue.

OBJECTIVE: To identify novel genes that are down-regulated in the testicular tissue of infertile men. DESIGN: Prospective study. SETTING: University-based reproductive clinics and genetics laboratory. PATIENTS: Nine patients with normal spermatogenesis, and 15 patients with maturation arrest (MA) or Sertoli cell-only syndrome (SCOS). INTERVENTION: Testicular samples of patients with the same histology were pooled for complementary DNA (cDNA) microarray analysis. MAIN OUTCOME MEASURE: Novel, down-regulated genes. RESULTS: In total, 300 genes were significantly down-regulated in SCOS or MA samples, and 10 novel sterility-related genes were identified. Of the 10 novel genes, 6 genes (Hs.126780, Hs.553658, Hs.274135, Hs.268122, Hs.531701, and Hs.171130) encode proteins with predictable functional domains, and all these functional domains are believed to correlate with spermatogenesis and/or spermiogenesis. Conversely, the other 4 genes (Hs.351582, Hs.407480, Hs.552781, and Hs.355570) do not encompass known functional domains. Two genes (Hs.407480 and Hs.552781) lack mouse orthologues. Most novel genes showed a testis-specific expression pattern in both mice and humans. Reverse transcription-polymerase chain reaction (RT-PCR) showed three distinct types of developmental stage-dependent expressions of message ribonucleic acid (mRNA) for these novel genes in murine testes. CONCLUSION: These 10 novel genes provide targets to elucidate novel pathways involved in human spermatogenesis.

Azoospermia↗

PubMed2006

Association of DAZL haplotypes with spermatogenic failure in infertile men.

OBJECTIVE: To identify novel DAZL single nucleotide polymorphisms (SNPs) and to compare allele/genotype frequencies, linkage disequilibrium (LD) characteristics, and DAZL haplotypes between fertile and infertile men. DESIGN: Prospective case study. SETTING: University genetics laboratory and reproductive clinics. PATIENT(S): Two hundred thirty-one infertile men and 191 men with proven fertility. INTERVENTION(S): Single strand conformation polymorphism and sequence analysis for DAZL gene polymorphism screening were done for all subjects enrolled. MAIN OUTCOME MEASURE(S): Novel SNPs, allele/genotype frequencies, LD characteristics, and DAZL haplotypes between fertile and infertile men. RESULT(S): Five SNPs were identified: 260A>G, 386A>G, 520+34c>a, 584+28c>t and 796+36g>a. SNP 386A>G was significantly associated with spermatogenic failure and was mainly heterozygous in infertile patients. The major haplotypes in infertile men were AACTA (45.8%), followed by AACCG, AAATA, AAACG, and GGACG for 260A>G/386A>G/520+34c>a/584+28c>t/796+36g>a. The major haplotypes for the control subjects were AACCG (41.7 %), AAATA, and AACTA. Of all haplotypes, five showed significant differences in frequency between infertile men and control subjects. Haplotypes AACTA, AAACG, and GGACG were overtransmitted in patients with spermatogenic failure, whereas haplotypes AACCG and AAATA were undertransmitted in these patients. CONCLUSION(S): Our study suggests the association of autosomal DAZL haplotypes with human spermatogenic failure.

DNA Mutational Analysis↗

PubMed2006

A modified supine position to speed hand assisted retroperitoneoscopic nephroureterectomy: the Johnnie Walker position.

PURPOSE: To minimize the operative time of hand assisted retroperitoneoscopic nephroureterectomy by avoiding position change we report an especially designed surgical position. MATERIALS AND METHODS: A total of 41 patients with upper tract transitional cell carcinoma who underwent hand assisted retroperitoneoscopic nephroureterectomy and bladder cuff resection were enrolled. Patients lay supine, and the flank and hip on the lesion side were elevated 30 degrees. The legs were extended and abducted in the Johnnie Walker position, allowing the operator to stand between them. Operation was completed via a 7 to 8 cm Gibson incision and 2 additional laparoscopic ports. RESULTS: All procedures were successful except 1 open conversion due to bleeding, in which there was no need to reposition the patient. Average patient age was 65.2 years (range 34 to 85), mean operative time was 207.6 minutes (range 130 to 345) and mean estimated blood loss was 166 ml (range 50 to 900). Simultaneous transurethral endoscopic procedures were performed in 11 patients in the same position. Time to oral intake and ambulation was 2.1 and 2.0 days, respectively. Two patients had postoperative complications, including pneumonia and wound hematoma in 1 each. No complication was related to the position. CONCLUSIONS: The Johnnie Walker position minimizes operative time by eliminating the delay caused by patient positioning and draping changes, allowing better coordination for the surgeon and assistant, and permitting more efficient use of the nondominant hand. The retroperitoneal approach prevents bowel interference in the visual field, making laparoscopic surgery in this modified supine position possible. Nephroureterectomy, bladder cuff resection and endoscopic procedures can be done with ease with the patient in this position.

Adult↗

PubMed2006

Uniform deletion junctions of complete azoospermia factor region c deletion in infertile men in Taiwan.

AIM: To determine the deletion junctions of infertile men in Taiwan with azoospermia factor region c (AZFc) deletions and to evaluate the genotype/phenotype correlation. METHODS: Genomic DNAs from 460 infertile men were examined. Bacterial artificial chromosome clones were used to verify the accuracy of polymerase chain reaction. Deletion junctions of the AZFc region were determined by analysis of sequence-tagged sites and gene-specific markers. RESULTS: Complete AZFc deletions, including BPY2, CDY1 and DAZ genes, were identified in 24 men. The proximal breakpoints were clustered between sY1197 and sY1192, and the distal breakpoints were clustered between sY1054 and sY1125 in all but one of the 24 men. The testicular phenotypes of men with complete AZFc deletion varied from oligozoospermia, to hypospermatogenesis, to maturation arrest. CONCLUSION: We identified a group of infertile men with uniform deletion junctions of AZFc in the Taiwan population. Despite this homogeneous genetic defect in the AZFc region, no clear genotype/phenotype correlation could be demonstrated.

Asian People↗

PubMed2006

Isolated posterior urethral injury: an unusual complication and presentation following male coital trauma.

We describe an unusual complication of coital trauma in a 29-year-old man who presented with a 3-year history of hematospermia and post-coital gross hematuria. Using urethroscopy under a semi-tumescent penis, an isolated urethral injury with active bleeding was detected at the prostatic urethra. The patient was successfully treated with transurethral fulguration. We suggest that isolated posterior urethral injury is one of the causes of male coital trauma, which might be asymptomatic when the penis is flaccid but show symptomatic bleeding when the penis is erect.

Adult↗

PubMed2005

GnRH in non-hypothalamic reproductive tissues.

Gonadotropin releasing hormone (GnRH) is a hypothalamic neuronal secretory decapeptide that plays a pivotal role in mammalian reproduction. GnRH and its analogues are used extensively in the treatment of hormone dependent diseases and assisted reproductive technology. Fourteen structural variants and three different forms of GnRH, named as hypothalamic GnRH or GnRH-I, mid brain GnRH or GnRH-II and GnRH-III across various species of protochordates and vertebrates have been recognised. The hormone acts by binding to cell surface transmembrane G protein coupled receptors (GPCRs) and activates Gq/11 subfamily of G proteins. Although hypothalamus and pituitary are the principal source and target sites for GnRH, several reports have recently suggested extra-hypothalamic GnRH and GnRH receptors in various reproductive tissues such as ovaries, placenta, endometrium, oviducts, testes, prostrate, and mammary glands. GnRH-II appears to be predominantly expressed in extra pituitary reproductive tissues where it produces its effect by PLC, PKA2, PLD, and AC cell signalling pathways. In these tissues, GnRH is considered to act by autocrine or paracrine manner and regulate ovarian steroidogenesis by having stimulatory as well as inhibitory effect on the production of steroid hormones and apoptosis in ovarian follicle and corpus luteum. In male gonads, GnRH has been shown to cause a direct stimulatory effect on basal steroidogenesis and an inhibitory effect on gonadotropin-stimulated androgen biosynthesis. Recent studies have shown that GnRH is more abundantly present in ovarian, endometrial and prostrate carcinomas. The presence of type-II GnRH receptors in reproductive tissues (e.g. gonads, prostrate, endometrium, oviduct, placenta, and mammary glands) suggests existence of distinct role(s) for type-II GnRH molecule in these tissues. The existence of different GnRH forms indicates the presence of distinctive cognate receptors types in vertebrates and is a productive area of research and may contribute to the development of new generation of GnRH analogues with highly selective and controlled action on different reproductive tissues and the target-specific GnRH analogues could be developed.

Animals↗

PubMed2004

Ring (Y) in two azoospermic men.

We have identified two azoospermic men with r(Y) in 312 infertile men presenting with non-obstructive azoospermia or oligozoospermia. Their karyotypes were 45,X [9]/46,X, r(Y)(p11q11) [11] (case 1), and 46,X,r(Y)(p11q11) (case 2), respectively. In both cases, the Yp breakpoints were located within the pseudoautosomal region. Both cases had extensive deletions of azoospermia factors (AZFs). Case 1 also had deletion of the putative growth controlling gene (GCY) and the Yq breakpoint was located between sY741 and USP9Y. The Yq breakpoint was located between sY105 and sY109 in case 2. Both cases did not have Turner stigmata except short stature in case 1. By a combination of cytogenetic and molecular genetic tools, we showed r(Y) arose from breakage in both arms of the chromosome with subsequent fusion of two broken ends of the centric fragment to form a continuous ring. Spermatogenic defects in men with r(Y) may result from deletion of Y-linked AZFs combined with synaptic failure.

Adult↗

PubMed2004

Expression profiles of the DAZ gene family in human testis with and without spermatogenic failure.

OBJECTIVE: To determine the expression profiles of the DAZ gene family in men with and without spermatogenic failure. DESIGN: Prospective case study. SETTING: University-based reproductive clinics and genetics laboratory. PATIENT(S): Thirty-four infertile men presenting with azoospermia. INTERVENTION(S): The mRNA transcript concentrations of the DAZ family genes (BOULE, DAZL, DAZ) and the housekeeping GAPDH gene in the testes of azoospermic men were examined by quantitative competitive-reverse transcription-polymerase chain reaction (QC-RT-PCR). The steady-state concentrations of mRNA encoding for each gene in each testicular sample were normalized by the amounts of GAPDH. MAIN OUTCOME MEASURE(S): Transcript ratios (gene/GAPDH) of BOULE, DAZL, and DAZ. RESULT(S): The transcript ratios for BOULE, DAZL, and DAZ were significantly decreased in tissues with spermatogenic failure (hypospermatogenesis, maturation arrest, and Sertoli cell-only). However, the ratios of BOULE/DAZL and DAZ/DAZL did not reveal any significant difference in all tissues. Three patients with DAZ deletion possess lower transcripts of BOULE and DAZL. CONCLUSION(S): All members of the DAZ gene family play important roles in human spermatogenesis. Decreased concentrations of DAZ family members in men with spermatogenic failure may be due to the secondary effect of germ cell loss, and transcriptional control of BOULE, DAZL, and DAZ are not altered in the various degrees of spermatogenic failure. Although the sample size is limited, no compensatory increase of DAZL or BOULE transcription was found in men with DAZ deletion.

Case-Control Studies↗

PubMed2004

Transcriptional levels of four Y chromosome-linked AZF genes in azoospermic men and their association with successful sperm retrieval.

OBJECTIVES: To investigate the transcriptional levels of four azoospermia factor genes in the testis of azoospermic men and to investigate the association between transcriptional levels and the results of sperm retrieval. METHODS: Thirty-eight azoospermic men with normal karyotype and without Y chromosome gene deletions were enrolled. The amounts of USP9Y (ubiquitin specific protease 9, Y chromosome), DBY (dead box on the Y), RBMY1 (RNA-binding motif on the Y, 1), and DAZ (deleted in azoospermia) transcripts were examined by quantitative competitive-reverse transcriptase-polymerase chain reaction. The steady-state concentrations of mRNA encoding for each gene in each testicular sample were normalized by the amounts of a housekeeping gene (glyceraldehyde phosphate dehydrogenase [GAPDH]). Differences in the transcript ratios (gene transcript/GAPDH transcript) among patients with different testicular histologic findings (normal spermatogenesis, hypospermatogenesis, maturation arrest, Sertoli cell-only syndrome) were analyzed. For each gene, the association between the transcript ratios and the results of sperm retrieval was evaluated. RESULTS: No statistically significant difference was found in the transcript ratios of USP9Y and DBY among the four histologic patient groups (P = 0.33 and P = 0.21, respectively). In contrast, statistically significant decreases were found in the transcript ratios of RBMY1 and DAZ in patients with spermatogenic failure (P = 0.0002 and P = 0.002, respectively). The transcript ratios of USP9Y and DBY were not associated with the results of sperm retrieval, and the transcript ratios of RBMY1 and DAZ revealed a positive association with successful sperm retrieval. CONCLUSIONS: The decreased transcriptional levels of RBMY1 and DAZ in patients with spermatogenic failure may reflect the generalized loss of germ cells. The transcriptional levels of RBMY1 and DAZ may have the potential of becoming useful parameters in the prediction of successful sperm retrieval.

Adult↗

PubMed2003

Prognostic values of p53 and HER-2/neu coexpression in invasive bladder cancer in Taiwan.

OBJECTIVES: To explore the clinical significance of p53 and HER-2/neu coexpression by immunohistochemistry in patients with invasive bladder cancer in Taiwan. METHODS: Paraffin-embedded tumor blocks were obtained from 67 patients with invasive bladder cancer subjected to radical cystectomy, bilateral lymph node dissection, and urinary diversion with or without systemic chemotherapy. Two observers (N.H.C. and T.S.T.), blinded to clinical outcome, reviewed the immunohistochemical staining for p53 (PAb1801) and HER-2/neu (Ab-17). The results were analyzed for progression-free survival and patient survival. RESULTS: Positive staining for p53 and HER-2/neu was found in 30 (44.8%) and 39 (58.2%) patients. In contrast to HER-2/neu, p53 expression was significantly associated with tumor grade and pathologic stage (p = 0.040 and 0.004, respectively), and tended to be related to the nodal status (p = 0.080). Most importantly, coexpression of p53 and HER-2/neu significantly correlated with nodal metastases (p = 0.020). Univariate and multivariate analysis revealed p53 and nodal status as two independent prognostic factors. Additionally, patients with p53 and HER-2/neu coexpression had the shortest time to relapse and overall survival, irrespective of whether adjuvant chemotherapy was given or not (p = 0.005 and 0.030). CONCLUSIONS: In invasive bladder cancer, p53 was an important prognostic factor since its expression correlated with tumor grade and stage, even nodal status, whereas HER-2/neu did not show prognostic significance. Tumors with p53 and HER-2/neu coexpression were associated with nodal metastases, probably resulting in decreased progression-free survival. Although some basic studies provide some important supports, studies including larger patient cohorts would still be required to prove the hypothesis that p53 and HER-2/neu-coexpressing tumors have a worse prognosis and are more resistant to a cisplatin-based multidrug regimen.

Adult↗

PubMed2002

Gene-based screening for Y chromosome deletions in Taiwanese men presenting with spermatogenic failure.

OBJECTIVE: To develop a simple and rapid protocol for detecting deletions of the Y chromosome and to evaluate the feasibility of gene-based screening in men with spermatogenic failure. DESIGN: Prospective case study. SETTING: University-based reproductive clinics and genetics laboratory. PATIENT(S): Two hundred two infertile men presenting with severe oligozoospermia and nonobstructive azoospermia. INTERVENTION(S): Fifteen gene-specific primers were used to detect deletions of Y chromosome genes in men with spermatogenic failure. A multiplex polymerase chain reaction amplification system was developed to facilitate rapid screening. Another 24 markers for sequence-tagged sites (STS) were used to ensure the adequacy of gene-based screening. MAIN OUTCOME MEASURE(S): Detection of deletions of Y chromosome genes. RESULT(S): Of 180 patients evaluated, 19 (10.6%) had deletions of one or more genes, including DFFRY, DBY, RBM1, DAZ, CDY1, and BPY2. A second round of STS-based screenings did not show an increase in the deletion rate but more clearly defined the extent of deletion in 14 of the 19 patients. In most patients, deletions detected by gene-based screening were similar to those detected by STS markers. CONCLUSION(S): Gene-based screening with multiplex polymerase chain reaction is a rational alternative for detecting deletions of Y chromosome genes in infertile men.

Adult↗

PubMed2002

Association of a single-nucleotide polymorphism of the deleted-in-azoospermia-like gene with susceptibility to spermatogenic failure.

Single-strand conformation polymorphism analysis of exon-containing genomic DNA segments of the deleted-in-azoospermia-like (DAZL) gene was performed in 160 infertile Taiwanese men presenting with severe oligozoospermia and nonobstructive azoospermia. An A-->G transition at nucleotide 386 in exon 3 was identified. The mutation is located within the RNA-recognition motif (aa 32-117) domain of the DAZL protein and will lead to Thr54-->Ala change (T54A) of DAZL protein. Analysis of cDNA from testicular tissue of infertile carriers showed absence of expression for the T54A allele, implying that the allele carrying T54A polymorphism is hardly, if ever, expressed. The frequencies of T54A allele in patients and the control group were 7.39% and 0.86%, respectively (P = 0.0003). The phenotypes varied significantly in cases with heterozygous T54A polymorphism, ranging from hypospermatogenesis and maturation arrest to Sertoli cell-only syndrome. A combination of DAZ gene deletion and T54A polymorphism did not worsen the phenotype. Our findings provide strong evidence for the role of the autosomal DAZL gene in human spermatogenesis.

Alleles↗

PubMed2002

Coronary arteriovenous fistula in pediatric patients: a 17-year institutional experience.

BACKGROUND AND PURPOSE: Coronary arteriovenous fistula (CAVF) is a rare congenital anomaly in pediatric patients. Its clinical manifestations vary considerably and its long-term outcome is not fully understood. This study sought to determine the natural history and long-term outcome in CAVF patients treated over a 17-year period at Cathay General Hospital in Taipei. MATERIALS AND METHODS: The medical records of all 10 pediatric patients (five boys and five girls aged between 15 days and 15 years) with CAVF treated from 1983 through 2000 at our hospital were reviewed. Data collected included symptoms and signs, the findings of electrocardiography, echocardiography, catheterization, and angiography, and surgical results. RESULTS: CAVF was diagnosed on the basis of color Doppler echocardiography in eight patients and by cardiac catheterization and angiography in two. Congestive heart failure was found in four patients and both myocardial ischemia and infarction were found in two patients. Most of the affected coronary arteries were tortuous and dilated with a mean diameter of 12.6 mm (range 5-40 mm). Under cardiopulmonary bypass, fistulous terminations were sutured in seven patients, three of whom were found to have multiple fistulous openings. Postoperative follow-up examinations revealed that all of the affected coronary arteries and fistulas remained dilated and tortuous, except in one patient. Two patients who had distal CAVF developed coronary thrombus, calcification, and ventricular aneurysm at 2 and 10 years after operation, respectively. Another patient developed fistulous recanalization 7 years after operation, but this abnormal channel had disappeared again 3 years after recanalization. One patient developed an iatrogenic CAVF 8 years after surgical repair of tetralogy of Fallot. CONCLUSIONS: Unlike adults, pediatric patients with CAVF tend to be symptomatic. Ligation of the fistulous termination alone does not reduce the size of the fistula. Our findings indicate that long-term follow-up is essential due to the possibility of postoperative recanalization, persistent dilation of the coronary artery and ostium, thrombus formation, calcification, and myocardial infarction. In addition, postoperative antiplatelet therapy is recommended, especially in patients with distal CAVF and abnormally dilated coronary arteries.

Adolescent↗