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Y L Tsai

Publications and source records attributed to Y L Tsai.

At least 19 recordsLinked to original sources
PubMed2003

A biomarker for the identification of swine fecal pollution in water, using the STII toxin gene from enterotoxigenic Escherichia coli.

This research developed a PCR method to identify swine fecal pollution in water, using a portion of the STII toxin gene from enterotoxigenic Escherichia coli as the target sequence. This method showed the gene to have a wide-spread geographical distribution and temporal stability; and the primers demonstrated high specificity, sensitivity, and reliability. A total of 110 DNA extracts from different animal fecal and human sewage samples were screened using the primers and no positives resulted. Centrifugation and filtration methods for concentrating E. coli seeded into stream, ocean, secondary effluent, and dairy lagoon waters resulted in detection limits at the femtogram and attogram levels. E. coli with the biomarker seeded into stream, ocean, and secondary effluent waters remained stable for approximately 2 weeks for all water types. Of the farm lagoon and waste samples tested, 94% were positive for the STII trait, regardless of the number of E. coli screened and 100% were positive when > or =35 E. coli isolates were screened. As the PCR product of the target sequence yielded a single band, the method is applicable to dot blot detection methodology, yielding great accuracy in determining the presence of swine fecal sources.

Animals↗
PubMed2002

A biomarker for the identification of cattle fecal pollution in water using the LTIIa toxin gene from enterotoxigenic Escherichia coli.

This research describes a method based on PCR to identify cattle fecal pollution in water using a portion of the heat labile toxin IIA (LTIIa) gene from enterotoxigenic Escherichia coli (ETEC). We describe the development of the primers and target. DNA extracts (221) from different animal fecal and human sewage samples were screened and showed no cross-reactivity. Minimum detection limits using centrifugation and filtration methods to concentrate E. coli seeded into stream, ocean, and secondary effluent waters were found to be at femtogram and attogram levels, respectively. Stability of the biomarker in stream, ocean, and secondary effluent waters was 2-4 weeks for all water types. Finally, 33 farm lagoon and waste samples were collected and 31 tested to validate the method; 93% were positive for the LTIIa trait when >1,000 E. coli were screened and 100% positive when >10(5) E. coli were screened. Prevalence of the toxin gene in the E. coli population affected the outcome of the analyses. The cow biomarker can be used in watershed studies to identify cattle waste with great accuracy if the appropriate numbers of E. coli are screened.

Animals↗
PubMed2001

Disruption of Plasmodium falciparum chitinase markedly impairs parasite invasion of mosquito midgut.

To initiate invasion of the mosquito midgut, Plasmodium ookinetes secrete chitinolytic activity to penetrate the peritrophic matrix surrounding the blood meal. While ookinetes of the avian malaria parasite Plasmodium gallinaceum appear to secrete products of two chitinase genes, to date only one chitinase gene, PfCHT1, has been identified in the nearly completed Plasmodium falciparum strain 3D7 genome database. To test the hypothesis that the single identified chitinase of P. falciparum is necessary for ookinete invasion, the PfCHT1 gene was disrupted 39 bp upstream of the stop codon. PfCHT1-disrupted parasites had normal gametocytogenesis, exflagellation, and ookinete formation but were markedly impaired in their ability to form oocysts in Anopheles freeborni midguts. Confocal microscopy demonstrated that the truncated PfCHT1 protein was present in mutant ookinetes but that the concentration of mutant PfCHT1 within the apical end of the ookinetes was substantially reduced. These data suggest that full-length PfCHT1 is essential for intracellular trafficking and secretion and that the PfCHT1 gene product is necessary for ookinetes to invade the mosquito midgut.

Animals↗
PubMed2001

Ion transport and morphological changes of mitochondria in brown adipocytes of warm- and cold-acclimatized obese Zucker rats.

Brown adipose tissue plays the dominant role in response to cold acclimatization through its capacity to produce heat. To demonstrate the cellular function for thermogenesis induced by cold acclimation in the brown adipose tissue of obese Zucker rats, we examined the changes for the area as well as the Na, K, Cl, and Ca concentrations in the mitochondria of brown adipocytes after the warm (25 degrees C, WG) and the cold acclimations (10 degrees C, CG). Moreover, the respiratory quotients (RQs) of these rats were measured. After the acclimations, the RQ in the CG was decreased and the oxygen consumption increased. A morphometric analysis of electron micrographs of brown adipocytes from the two groups of rats showed a marked increase in the area of the mitochondria in the CG. An electron probe X-ray microanalysis showed an increase in the Ca concentration and decreases in the Na and K concentrations in the matrix of the mitochondria of the cells in the CG. These results suggest that the reduction in the RQ of obese Zucker rats acclimated to cold is the consequence of the metabolism of a large quantity of lipid in the brown adipocytes. Our data also indicate that the observed change in the mitochondrial area and the increase for Ca in the mitochondria were associated with the cold-induced thermogenesis in brown adipocytes of obese Zucker rats.

Acclimatization↗
PubMed2001

Pregnancy after intentional cryopreservation of percutaneous sperm aspiration specimens and intracytoplasmic sperm injection. A report of two cases.

BACKGROUND: Microsurgical epididymal sperm aspiration (MESA) and percutaneous epididymal sperm aspiration (PESA) are two methods of obtaining spermatozoa from patients with irreparable obstructive azoospermia. Intentionally using frozen-thawed spermatozoa obtained from MESA had been reported to be successful. With minimal invasiveness, intentionally cryopreserved PESA specimens and intracytoplasmic sperm injection (ICSI) were carried out in two cases. CASES: Two cases of irreparable obstructive azoospermia received PESA, and the spermatozoa were cryopreserved intentionally. Successful ICSI was performed later, utilizing frozen-thawed spermatozoa. CONCLUSION: PESA and ICSI are promising methods for these patients. The major advantages are minimal invasiveness and flexibility for further treatment.

Adult↗
PubMed2000

Constituents from the leaves of Aristolochia elegans.

One new biphenyl ether, aristogin C (1), and two new porphyrins, aristophylls A (2) and B (3), as well as 11 known compounds, were isolated from the leaves of Aristolochia elegans. Their structures were elucidated according to the spectroscopic (NMR and MS) analyses or by comparison with literature values.

Chromatography, High Pressure Liquid↗
PubMed2000

In vitro maturation and fertilization of immature oocytes: a comparative study of fertilization techniques.

PURPOSE: Our purpose was to investigate the factors influencing maturation and fertilization of immature oocytes. METHODS: Immature oocytes were obtained from women undergoing cesarean section. They were cultured in the maturation medium either with or without cumulus cells. After maturation to metaphase II, they were randomly fertilized by in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI). RESULTS: After incubation for 48 hr, 441 oocytes (42.8%) reached metaphase II. Among them, 56.6% of cumulus-enclosed oocytes, but only 29.2% of denuded oocytes, reached metaphase II. Of the 289 cumulus-enclosed oocytes, the fertilization rates by IVF and ICSI were 56.3 and 84.1%, respectively (P < 0.01). Of the 152 denuded oocytes, the fertilization rates by IVF and ICSI were 39.5 and 84.5%, respectively (P < 0.01). The cleavage rates, however, were similar. CONCLUSIONS: Cumulus cells are beneficial in the maturation of human oocytes in vitro and that ICSI increases the fertilization rate for the in vitro matured oocytes. The developmental potential of the fertilized oocytes, however, is similar irrespective of the fertilization method or the presence or absence of cumulus cells.

Adult↗
PubMed2000

Methotrexate for cesarean scar pregnancy after in vitro fertilization and embryo transfer. A case report.

BACKGROUND: Cesarean scar pregnancy is an exceedingly rare occurrence. We present the first case of cesarean scar pregnancy following in vitro fertilization-embryo transfer (IVF-ET). CASE: A 40-year-old woman with a history of a previous cesarean section presented with five years of unexplained infertility. The patient complained of abdominal pain 16 days after embryo transfer. Ultrasonography revealed a gestational sac with cardiac activity located outside the lower segment of the uterus. Dilatation and curettage was performed due to misdiagnosis of inevitable abortion. Two weeks later, repeated sonography demonstrated a sacculus, 4.07 x 4.07 cm, within the uterine isthmus with only 7.1 mm of thickness separating the sac from the urinary bladder. Normal cervical length without ballooning was noted. Cesarean scar pregnancy was diagnosed. Local injection of methotrexate (MTX) under ultrasound guidance was performed. Plasma beta-hCG levels declined from 23,328 to 8 mlU/mL within two months. CONCLUSION: For women with cesarean scar pregnancy who desire fertility, conservative treatment using MTX is an excellent choice.

Abortifacient Agents, Nonsteroidal↗
PubMed2000

Prenatal diagnosis of meconium peritonitis in a twin pregnancy after intracytoplasmic sperm injection. A case report.

BACKGROUND: Meconium peritonitis occurring in pregnancies following artificial reproductive techniques (ART) is rare. We report the first case of meconium peritonitis following intracytoplasmic sperm injection (ICSI). CASE: A 37-year-old woman attended our in vitro fertilization (IVF) program because her husband suffered from hypospermatogenetic azoospermia due to cancer surgery and radiotherapy. The patient achieved a twin pregnancy through ICSI from testicular sperm extraction at our IVF center. Meconium peritonitis, fetal ascites, polyhydramnios, bowel dilatation, hydrocele and intraabdominal calcification were noted in one of the twins on ultrasound at 30 weeks' gestation. Cesarean section due to breech presentation in labor was performed at 36 weeks' gestation. A normal female and male infant with a distended abdomen were delivered. Emergency laparotomy was performed on the male twin because of dyspnea. A 0.2-cm perforation was found in the terminal ileum. Ileotomy was performed and closed after 27 days. CONCLUSION: Prenatal diagnosis of meconium peritonitis is possible through careful ultrasonographic examination, and early surgical intervention and intensive postoperative support are required to improve the prognosis.

Adult↗
PubMed1999

Percutaneous epididymal sperm aspiration in psychogenic anejaculation during IVF. A report of two cases.

BACKGROUND: Psychogenic anejaculation on the day of oocyte retrieval is uncommon in in vitro fertilization (IVF) programs. Before the use of intracytoplasmic sperm injection (ICSI), either the cycle had to be canceled or a sperm donor recruited. CASES: Two couples were enrolled for IVF. On the day of oocyte retrieval, the male partners developed psychogenic anejaculation. CONCLUSION: In cases of psychogenic anejaculation during IVF, percutaneous epididymal sperm aspiration can be utilized to obtain sperm for ICSI.

Adult↗
PubMed1998

Potential use of repeated fluorescence in situ hybridization in the same human blastomeres for preimplantation genetic diagnosis.

OBJECTIVE: To assess the feasibility of repeated fluorescence in situ hybridization (FISH) procedures in the same nucleus of a human blastomere. DESIGN: Three consecutive FISH procedures were performed in the same human blastomere by using direct label fluorescence CEP and WCP probes (Vysis). SETTING: Hospital-based private IVF program. PATIENT(S): Twenty-eight infertile couples who underwent conventional IVF in our center. INTERVENTION(S): Embryos from oocytes with three pronuclei after in vitro insemination were used in this study. MAIN OUTCOME MEASURE(S): The rates of nuclear loss, present signals, and absent signal were examined. RESULT(S): In group 1, the rates of presence of signals were 94% after the first FISH, 92% after the second FISH, and 88% after the third FISH. In group 2, the rates of presence of signals were 96% after the first FISH, 93% after the second FISH, and 87% after the third FISH. There was no statistically significant difference in the rates of nuclear loss, present signals, and absent signal between three consecutive FISH procedures and between CEP and WCP probes. CONCLUSION(S): Six or more chromosomes of a single blastomere may be examined with use of this repeated FISH procedure, which may be important for preimplantation genetic diagnosis.

Blastomeres↗
PubMed1998

Feasibility study of repeated fluorescent in-situ hybridization in the same human blastomeres for preimplantation genetic diagnosis.

In order to increase the number of chromosomes examined in each blastomere, we have developed a repeated fluorescent in-situ hybridization (FISH) procedure by which six or more chromosomes can be analysed per blastomere of a human embryo. Three consecutive FISH procedures with directly-labelled fluorescent Vysis DNA probes were carried out for examination of chromosomes X, Y, 11, 13, 18 and 21 in the same blastomeres (n = 126) and lymphocytes (n = 164). Based on the initial number of nuclei, the percentages of nuclear loss and presence of signals were 3 and 92% respectively in blastomeres; 6 and 91% respectively in lymphocytes after the first FISH; 7 and 87% respectively in blastomeres and 10 and 86% respectively in lymphocytes, after the second FISH. These percentages were 13 and 78% respectively in blastomeres and 14 and 81% respectively in lymphocytes after the third FISH. The FISH procedure was repeated successfully in a couple for preimplantation genetic diagnosis of chromosomal aneuploidies in biopsied blastomeres of their embryos in our clinic. In conclusion, it is feasible to carry out repeated FISH procedures in the same blastomeres. Six or more chromosomes of a single blastomere may be examined using this procedure.

Adult↗
PubMed1998

Quantification of poliovirus in seawater and sewage by competitive reverse transcriptase--polymerase chain reaction.

Reverse transcriptase-polymerase chain reaction (RT-PCR) has been used extensively to detect enteric viruses in environmental samples. Advantages of RT-PCR include its high detection sensitivity and rapid turn-around time. However, unlike traditional cell culture, RT-PCR has not provided quantitation and infectivity information. In this study, we have developed a quantitative RT-PCR method that can be used to determine the amount of poliovirus RNA in environmental samples. An RNA internal standard for poliovirus RT-PCR was designed and obtained through genetic engineering. Serial dilutions of RNA internal standard templates were amplified with a 5'-carboxyfluorescein-labeled poliovirus downstream primer and a nonlabeled poliovirus upstream primer in the RT-PCR. The fluorescent light intensity of labeled RT-PCR products was quantified using an ABI DNA sequencer with GeneScan software. The internal standard was coamplified with poliovirus in the RT-PCR, allowing for enumeration of the poliovirus RNA present in the seawater and sewage samples. This method, using a cloned internal standard and specified primers in the PCR, may be applied to quantify other microorganisms in environmental samples. Although quantitative RT-PCR has begun to be used more extensively for detecting pathogens in clinical samples, the complex nature of many environmental samples has limited the sample range of the effectiveness of quantitative RT-PCR.

Environmental Microbiology↗
PubMed1997

Pregnancy after immature oocyte donation and intracytoplasmic sperm injection.

OBJECTIVE: To report a case of pregnancy from in vitro-matured primary oocytes fertilized by ICSI. The pregnancy occurred in a woman who was in an oocyte donation program; the woman's husband had normal sperm parameters. DESIGN: Case report. SETTING: Private general hospital affiliated with a university hospital. PATIENT(S): A recipient with premature ovarian failure, a recipient's husband with normal sperm, and a pregnant woman who donated her oocytes. INTERVENTION(S): Aspiration of immature oocytes during cesarean section, in vitro culture for maturation, ICSI of matured oocytes, coculture of fertilized oocytes. MAIN OUTCOME MEASURE(S): Fertilization of oocytes by ICSI, and cleavage of embryos by Vero cell coculture. RESULT(S): Two of seven immature oocytes became metaphase II oocytes, and both were fertilized by ICSI. The two zygotes were cocultured on Vero cells to become grade 1 two-cell embryos. Pregnancy was obtained after transfer. CONCLUSION(S): More studies are necessary to clarify whether ICSI can increase the fertilization rate of in vitro-matured primary oocytes, and to clarify the role of coculture in fertilization.

Adult↗
PubMed1997

High fertilization rate obtained after intracytoplasmic sperm injection with 100% nonmotile spermatozoa selected by using a simple modified hypo-osmotic swelling test.

OBJECTIVE: To report a high fertilization rate after intracytoplasmic sperm injection (ICSI) in patients with 100% nonmotile spermatozoa selected by a simple modified hypo-osmotic swelling test. DESIGN: Clinical study. SETTING: Hospital-based IVF center. PATIENT(S): Three couples with infertility due to asthenospermia. INTERVENTION(S): The hypo-osmotic swelling test with 150-mOsm NaCl solution was used to select viable spermatozoa before ICSI. Three patients provided semen samples and one of these three also had a testicular biopsy. MAIN OUTCOME MEASURE(S): Selection of viable spermatozoa using the hypo-osmotic swelling test with 150-mOsm NaCl solution for ICSI. RESULT(S): No motile spermatozoa were found in three ejaculated semen samples and one testicular biopsy. Fifty-seven metaphase-II oocytes were injected with hypo-osmotic swelling test-positive ejaculated or testicular spermatozoa. Fifty-five (96.5%) of these oocytes were intact after injection. Forty-two (76.4%) of 55 oocytes showed two pronuclei, and 40 of the 42 fertilized oocytes cleaved. One patient had all embryos cryopreserved because of the risk of hyperstimulation; two other patients had embryos transferred. One ongoing pregnancy resulted. CONCLUSION: This hypo-osmotic swelling test with 150-mOsm NaCl solution is a simple and efficient method for selection of viable spermatozoa. A high fertilization rate can be obtained using ICSI with viable spermatozoa selected by using this hypo-osmotic swelling test.

Cryopreservation↗
PubMed1997

Establishment of an optimal hypo-osmotic swelling test by examining single spermatozoa in four different hypo-osmotic solutions.

In order to find an optimal hypo-osmotic swelling test (HOST) and to identify viable sperm cells from patients with asthenozoospermia for intracytoplasmic sperm injection (ICSI), we tested single motile and non-motile spermatozoa in four hypo-osmotic solutions by micromanipulation. The four solutions were: A, H2O; B, 50 mOsm NaCl; C, 150 mOsm NaCl and D, 150 mOsm sodium citrate and fructose. Eosin Y staining was then carried out for evaluation of viability of the spermatozoa after HOST. Using motile spermatozoa, no statistical difference was found in HOST-positive spermatozoa between these four solutions. There were more viable sperm cells after HOST in solutions C and D, as noted by Eosin Y staining. After non-motile spermatozoa were incubated for 1 min in the four solutions, HOST with solution C gave the best results for identification of viable sperm cells compared to the other three solutions. When motile spermatozoa were incubated in solution C or solution D for 30 min, the result of HOST with solution C (10.8% dead spermatozoa) was superior to that of solution D (49.1% dead spermatozoa). In conclusion, the HOST protocol using 150 mOsm NaCl (solution C) for 1 min yielded the best results for selection of viable spermatozoa. This procedure should be used for selection of viable spermatozoa for ICSI in patients with 100% non-motile spermatozoa.

Cell Membrane↗
PubMed1997

Outcome of in-vitro culture of fresh and frozen-thawed human testicular spermatozoa.

The effect of in-vitro culture on the motility and morphology of fresh and frozen-thawed human testicular spermatozoa obtained from obstructive azoospermic patients and on the motility of testicular spermatozoa obtained from non-obstructive azoospermic patients was evaluated. The outcome of intracytoplasmic sperm injection (ICSI) with fresh and frozen-thawed human testicular spermatozoa was studied. The results showed that significant improvement of sperm morphology and motility was observed in culture of fresh (n = 17) and frozen-thawed (n = 15) testicular sperm samples obtained from patients with obstructive azoospermia. The motility of cultured testicular spermatozoa reached a peak at 72 h without the need for special media. In six of 20 samples obtained from patients with non-obstructive azoospermia, improvement of sperm motility was observed. When only non-motile testicular spermatozoa were cultured, they all remained non-motile (n = 9). In patients with obstructive azoospermia, fertilization rates of 80 and 81% were obtained using ICSI with fresh and frozen-thawed testicular spermatozoa respectively. Clinical pregnancies were observed in four out of nine patients with fresh testicular spermatozoa and two out of five patients after using frozen-thawed spermatozoa. When fresh testicular spermatozoa obtained from patients with non-obstructive azoospermia were used for ICSI, the fertilization rate was 68% and two out of seven patients achieved clinical pregnancies. In conclusion, the morphology and motility of fresh and frozen-thawed testicular spermatozoa in patients with obstructive azoospermia can be significantly improved after in-vitro culture. The outcome of in-vitro culture of testicular spermatozoa in patients with non-obstructive azoospermia is unpredictable. In-vitro culture of non-motile testicular spermatozoa is not successful so far. The outcome of ICSI with fresh and with frozen-thawed testicular spermatozoa was similar.

Adult↗