Biomedical subjects

H R Lin

Publications and source records attributed to H R Lin.

31 records · Page 2Linked to original sources

PubMed1992

Effect of the number and depth of embryos transferred and unilateral or bilateral transfer in tubal embryo transfer (TET).

PURPOSE: Our purpose was to evaluate the possible effects of the number of embryos transferred, the depth of embryos placed within the tube(s), and unilateral or bilateral tubal transfer on pregnancy initiation in tubal embryo transfer (TET). METHODS: One hundred eight consecutive TET cycles were analyzed. Oocyte retrievals were carried out by transvaginal ultrasound-guided aspiration of follicles. Forty-eight hours after oocyte retrieval, the developing embryos at the stage of two to four cells were transferred into the fallopian tube(s) by laparoscopy. A maximum of four embryos was transferred to each patient. RESULTS: The pregnancy rates were similar among the cycles in which two, three, or four embryos were transferred. In addition, there was no significant difference in the pregnancy rate whether the embryos were deposited > 4 cm or between 3 and 4 cm into the tube(s). Although the pregnancy rate was greater in cycles of bilateral tubal transfer, the difference from that of unilateral transfers was not significant. CONCLUSION: Our data indicate that when two to four embryos were transferred and the embryos were placed > or = 3 cm within the tube(s), unilateral or bilateral tubal transfer had little influence on the ultimate success of TET.

Embryo Transfer↗

PubMed1992

Pregnancy after transfer of frozen-thawed human embryos.

Cryopreservation of human embryos has been successfully applied in in vitro fertilization (IVF) and embryo transfer (ET) programs at the National Taiwan University Hospital since 1988. Our preliminary results with 120 frozen-thawed embryos in 31 transfer cycles showed that the survival rate of frozen embryos was 66%. Following transfer, the implantation rate and clinical pregnancy rate were 6.5% and 13%, respectively. Four clinical pregnancies and one preclinical pregnancy following a frozen-thawed embryo transfer were achieved. Two normal male babies have been delivered and another pregnancy is progressing without any problem.* Unfortunately, one pregnancy was terminated due to intrauterine fetal death discovered at the 10th week of gestation; chromosome abnormality (47, XX, +5) of the fetus was found. The single preclinical pregnancy showed an elevation of serum beta-human chorionic gonadotropin levels for three consecutive weeks following ET, but no definite gestational sac was visualized by transvaginal ultrasound.

Adult↗

PubMed1991

Translaparoscopic tubal embryo transfer: preliminary experience at National Taiwan University Hospital.

Forty-six couples with various causes of infertility were treated by tubal embryo transfer. Oocyte retrievals were carried out under ultrasound guidance transvaginally and embryos were transferred 48 hours later by laparoscopy into fallopian tubes. Totally 52 cycles were stimulated and 45 retrievals were performed with an average of 8.1 oocytes per retrieval. The average fertilization rate was 54.8%. The implantation rate was 23.8% and the pregnancy rate was 53.5% per transfer. The pregnancy rate per transfer was comparable whether 3 or 4 embryos were transferred. Nine (39.1%) of the 23 pregnancies had multiple pregnancies. Six cases (26.1%) aborted in the first trimester and the remaining 17 were ongoing or term delivery.

Adult↗

PubMed1991

Treatment of patients with unexplained infertility: gamete intrafallopian transfer (GIFT) versus tubal embryo transfer (TET).

This study compares the results of 65 cycles of gamete intrafallopian transfer (GIFT), and 19 cycles of tubal embryo transfer (TET) in couples with unexplained infertility (UI). Oocyte retrievals were carried out by laparoscopy in GIFT and transvaginally in TET, in which the embryos were transferred by laparoscopy into the fallopian tubes 48 hours later. The mean age, duration of infertility, serum estradiol levels on the day of human chorionic gonadotropin administration, number of large follicles (mean diameter greater than 10 mm) and the number of oocytes recovered were similar between these two groups. From the 65 GIFT cycles, 20 clinical pregnancies resulted (30.8%). From the 19 cycles of TET, 10 conceptions occurred (52.6%). The implantation and pregnancy rates after TET were higher than that after GIFT, but the differences were not statistically significant. The data suggest that GIFT has a similar success rate to TET in couples with UI.

Adult↗

PubMed1991

The use of a long-acting gonadotropin-releasing hormone analog(D-Trp-6-LHRH) for improvement of ovarian stimulation in assisted conception programs.

To assess the efficacy of gonadotropin-releasing hormone analog (GnRHa) as an adjuvant in controlled ovarian stimulation in assisted conception programs, 114 infertile patients, who were treated by in vitro fertilization and embryo transfer (n = 61) or tubal embryo transfer (n = 53), were randomized sequentially to receive ovarian stimulation according to two protocols. In protocol 1 (n = 57), long-acting GnRHa (D-Trp-6-LHRH) microcapsules were administered intramuscularly at menstruation and ovarian stimulation using follicle-stimulating hormone (FSH) and human menopausal gonadotropin (hMG) was started 2 to 3 weeks later when the pituitary was completely suppressed. In protocol 2 (n = 57), patients received FSH and hMG from day 3 of the cycle without GnRHa pre-treatment. We found that premature luteinization did not occur in patients treated with protocol 1, and the number of cycles cancelled was also decreased. The days of ovarian stimulation and the amount of hMG required to achieve adequate follicular development were significantly higher in protocol 1 than that in protocol 2. Similarly, the mean serum estradiol levels on the day of human chorionic gonadotropin administration, number of large follicles (mean diameter greater than 10 mm), number of oocytes recovered and number of embryos obtained were also significantly higher in patients treated with protocol 1. The data suggest that the use of D-Trp-6-LHRH as an adjuvant in ovarian stimulation is associated with a lower incidence of cycle cancellation and an improvement in ovarian response in assisted conception programs.

Adult↗

PubMed1988

Effects of [D-Arg6, Trp7, Leu8, Pro9NEt]-luteinizing hormone-releasing hormone (sGnRH-A) and [D-Ala6, Pro9NEt]-luteinizing hormone-releasing hormone (LHRH-A), in combination with pimozide or domperidone, on gonadotropin release and ovulation in the Chinese loach and common carp.

The effects of LHRH-A and sGnRH-A alone and in combination with the dopamine receptor antagonists pimozide (PIM) and domperidone (DOM) on stimulation of gonadotropin (GtH) secretion and ovulation in Chinese loach (Paramisgurnus dabryanus) and common carp (Cyprinus carpio) were studied. When tested in the absence of a dopamine receptor antagonist, sGnRH-A was about 10-fold more potent than LHRH-A in stimulating GtH secretion in loach, whereas these peptides were of similar effectiveness in common carp. Both peptides were effective alone in inducing ovulation in loach, but were ineffective in common carp. PIM and DOM stimulate a small but significant increase in serum GtH, and greatly potentiate the effects of LHRH-A and sGnRH-A on GtH secretion and ovulation in both species. DOM was of equal or somewhat greater potency than PIM in potentiating the action of releasing hormone agonists in loach; however, DOM had markedly greater effectiveness in common carp. sGnRH-A in the presence of DOM was more effective than LHRH-A in stimulating GtH secretion and ovulation in common carp. The present studies suggest that there are marked differences in the relative contribution of GnRH and dopamine in the control of GtH secretion in loach and common carp, and indicate in particular that the more intense dopaminergic inhibitory control of GtH release in common carp modifies the responsiveness of the pituitary to GnRH peptides.

Animals↗

PubMed1987

Primary structure of common carp prolactins.

The complete amino acid sequence of common carp (Cyprinus carpio) prolactin (PRL) has been determined. One milligram of carp PRL was reduced, carboxymethylated, and then cleaved with cyanogen bromide and several enzymes. Another milligram of carp PRL was digested with lysyl endopeptidase. The resulting fragments were separated by reverse-phase high-performance liquid chromatography and subjected to sequence analysis by the automatic Edman method with a gas-liquid sequencer and the manual DNS-Edman method. The carp PRL consists of 186 amino acid residues with two disulfide linkages formed between residues 46-160 and 177-186. In addition, it lacks the linkage in the amino-terminal portion of mammalian prolactins, as do salmon and tilapia PRLs, and shows 77% sequence identity with salmon PRL and 36% identity with mammalian PRLs. The sequence comparison has been performed with 190 alignment positions. Four conserved segments of the alignment positions 1-32, 46-66, 71-94, and 155-182 that were found between salmon and mammalian PRLs are further confirmed in carp PRL. Variant residues are clustered in the region of residues 98-143 which has 48% sequence identity with salmon PRL and only 2% with mammalian PRL.

Amino Acid Sequence↗

PubMed1986

Effects of [D-Ala6, Pro9-NEt]-LHRH and catecholaminergic drugs on gonadotropin secretion and ovulation in the Chinese loach (Paramisgurnus dabryanus).

The effects of [D-Ala6,Pro9-NEt]-LHRH (LHRH-A) alone and in combination with drugs which influence the actions of dopamine or the synthesis of catecholamines on gonadotropin (GtH) secretion and ovulation in the loach (Paramisgurnus dabryanus) were investigated. LHRH-A alone stimulated an increase in serum GtH levels in the loach, but was a relatively ineffective treatment for the induction of ovulation. Injection of the dopamine receptor antagonist pimozide caused a marked potentiation of the GtH-release response to LHRH-A, and combined injections of pimozide and LHRH-A were an effective treatment for the induction of ovulation. Reserpine, a drug which causes depletion of catecholamines from presynaptic terminals, also caused a marked potentiation of the GtH-release response to LHRH-A and combined treatment induced ovulation. Similarly, administration of alpha-methyl-para-tyrosine to block conversion of tyrosine to L-dopa, or carbidopa to block conversion of L-dopa to dopamine, potentiated the GtH-release response to LHRH-A and induced ovulation. In contrast, the use of diethyldithiocarbamate, to block conversion of dopamine to norepinephrine, failed to augment the action of LHRH-A on GtH release and ovulation. The present results provide further evidence to suggest that dopamine functions as a gonadotropin release-inhibitory factor in teleosts, and demonstrate that the use of drugs which block either the synthesis or the actions of dopamine potentiates the action of LHRH-A in teleosts.

Animals↗

PubMed1983

Effects of LH-RH and des-Gly10[D-Ala6]LH-RH-ethylamide on plasma gonadotropin levels and oocyte maturation in adult female coho salmon (Oncorhynchus kisutch).

Plasma gonadotropin (GtH) levels and state of oocyte development were determined in adult female coho salmon following single intraperitoneal injections of LH-RH or its superactive analog des-Gly10[D-Ala6]LH-RH-ethylamide (LH-RHA DAla6). The peptides injected at dosages of 1.0 or 0.2 mg LH-RH and 0.2 or 0.02 mg LH-RHA DAla6/kg bw elevated plasma GtH by 1.5 hr postinjection. The response to the analog was of longer duration. Plasma GtH levels returned to basal levels 24 hr following LH-RH injection while elevated plasma GtH levels were maintained for at least 96 hr in response to the analog. Only those fish injected with LH-RHA DAla6 showed an accelerated rate of germinal vesicle breakdown (GVBD). Based on their relative effects on GVBD, LH-RHA DAla6 has at least 50 times the biological potency of LH-RH in adult female coho salmon.

Animals↗

PubMed1981

Studies on mechanism of action of luteinizing releasing hormone (LH-RH) in ovulation of fish--intracellular distribution of LH-RH-A in pituitary gonadotrophs as revealed by electron-microscopic autoradiography.

The results of competitive bending experiment and the electron-microscopic autoradiographic studies show that the peptide hormone, LH-RH-A (a nonapeptide), could be internalized into the gonadotrophs of the pituitary gland of the mud-carp (Cirrhrinus molitorella). It is demonstrated that the labeled peptide, 125I-LH-RH-A, is internalized not only into the cytoplasm, but also into the nucleus, apparently via the nuclear pores. It is, therefore, suggested that the peptide hormone might act directly on the genome either in the form of a hormone-receptor complex or of a single molecule.

Animals↗

PubMedDate not supplied

Microinjection of human sperm into perivitelline space of hamster eggs: comparison with zona-free hamster egg penetration of human sperm.

Micromanipulation of human sperm and oocyte has been utilized to facilitate fertilization of those patients with male factor due to oligoasthenospermia or those patients with repeated fertilization failure in an in vitro fertilization (IVF) program. Before manipulating human gametes, one needs experience with animal models. Our objective was to perform subzonal insertion of human sperm into hamster eggs and to compare the result with that of sperm penetration assay (SPA) using zona-free hamster eggs. Semen samples were obtained from 15 fertile donors with normal semen analysis and the motile sperm were collected by swim-up procedure. Microinjection was performed by injecting a varied number of sperm into the perivitelline space of 222 hamster eggs pretreated with sucrose solution (0.1 M). The rate of damage of eggs during microinjection was 7.2% (16/222). The rates of penetration in the microinjection group were 5.1% (4/79) for 1-5 sperm injected, 10.9% (11/101) for 6-10 sperm injected, and 11.5% (3/26) for 11-15 sperm injected. The average rate of penetration per egg was 8.7% (18/206), and the polyspermic rate was 11.1% (2/18). Simultaneously SPA was performed in each sample of semen as a positive control, and the average rate of penetration of SPA was 51.4% (108/210). The rate of penetration in the microinjection group was significantly smaller (p < .05) than that in the SPA group. Whether the penetration rate and polyspermic rate in a hamster model reflect similar results in human oocyte requires further investigation. However, the hamster egg provides an ideal model to develop a micromanipulation technique for human beings.

Animals↗

PubMedDate not supplied

Acrosin activity of human sperm did not correlate with IVF.

To evaluate the predicting value of sperm acrosin activity in human, the acrosin activity index (AAI) was measured in 95 semen samples from patients participating in an IVF program. All patients had at least two mature oocytes. Of 95 patients, 84 had successful fertilization and 11 failed to fertilize all oocytes in vitro. The numbers of mature oocytes were similar between fertilization and nonfertilization groups. The mean AAI, measured using a commercially available (Accu-Sperm) acrosin activity assay, was greater in the fertilization group than in the nonfertilization group, but the difference was not significant. There was no correlation between AAI and the in vitro fertilization rate of mature oocytes. The relation between AAI and semen parameters also showed no significant difference. It would appear that measurement of AAI inaccurately reflects in vitro fertilizability of human sperm.

Acrosin↗

PubMedDate not supplied

Correlation between sperm morphology using strict criteria in original semen and swim-up inseminate and human in vitro fertilization.

To study the value of sperm morphology using strict criteria in raw semen and in swim-up inseminate of human in vitro fertilization (IVF), 135 cycles of IVF with normal sperm concentration and motility were recruited. At least two mature oocytes were recovered in each cycle. The correlation between the percentages of normal forms and fertilization rates of mature oocytes was analyzed. The results demonstrate that the percentage of normal forms in both the raw semen and swim-up sample of patients with poor fertilization was significantly lower than in those with acceptable fertilization. The percentages of normal forms both in raw semen and in swim-up sample were significantly correlated with fertilization rates in vitro, however, the former seemed to have a better correlation (r = .51 and .19, respectively). Regarding the percentages of normal forms in raw semen, the fertilization rate in patients with normal forms < 4% was 6 +/- 11%, for 4-14% it was 58 +/- 36%, and for > 14% it was 88 +/- 20%. The fertilization rates were significantly different among these three groups of patients. The evaluation of sperm morphology using strict criteria in raw semen before IVF is predictive of fertilization outcome and may also help doctors to choose an optimal method of treatment for patients.

Female↗