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Biomedical subjects

P C Ho

Publications and source records attributed to P C Ho.

At least 19 recordsLinked to original sources

Intrauterine insemination after ovarian stimulation as a treatment for subfertility because of subnormal semen: a prospective randomized controlled trial.

OBJECTIVE: To determine whether intrauterine insemination (IUI) after ovarian stimulation with human menopausal gonadotropin (hMG) gives a better pregnancy rate (PR) than natural intercourse in couples with subfertility because of subnormal semen. DESIGN: Prospective randomized controlled trial. SETTING: University based subfertility clinic. PATIENTS: Couples with subnormal semen as the only identifiable cause of subfertility. INTERVENTIONS: In control cycles, the couples had natural intercourse. In IUI cycles, IUI was performed after ovarian stimulation with hMG and human chorionic gonadotropin. MAIN OUTCOME MEASURE: The clinical PRs and complications of IUI cycles and control cycles were compared. RESULTS: There were six clinical pregnancies in the 42 IUI cycles, whereas there was no clinical pregnancy in the 42 control cycles. The clinical PR in IUI cycles (14.3% per cycle) was significantly higher than that in control cycles (0%). Six patients (14.3%) developed moderate degree of ovarian hyperstimulation syndrome in IUI cycles. CONCLUSION: Intrauterine insemination after ovarian stimulation with hMG is useful in treatment of subfertile couples with subnormal semen.

Adult

Improved development of human embryos in vitro by a human oviductal cell co-culture system.

This study was undertaken to determine the effect of co-culture with human oviductal cells on human embryos. Spare embryos from gamete intra-Fallopian transfer (GIFT), pronuclear stage transfer (PROST) and in-vitro fertilization/embryo transfer (IVF/ET) programmes were either cultured in serum-supplemented Earle's balanced salt solution alone, or co-cultured in the same solution with oviductal cells from the pronuclear stage (day 1 post-insemination) or two- to four-cell stage (day 2 post-insemination). The co-cultured embryos appeared to have a higher developmental potential (higher rate of blastocyst formation and lower fragmentation rate), although there was no statistical difference in their rate of development, degree of fragmentation and stages attained, when compared with conventionally cultured embryos. The percentage of hatching blastocysts was significantly higher (P less than 0.05, Fisher's exact test) for embryos co-cultured from day 1 post-insemination (38%) than for embryos which had not been co-cultured (7%). The blastocyst hatching rate for embryos co-cultured from day 2 post-insemination was 15%. It was therefore concluded that co-culture of human embryos with oviductal cells could improve the development of the embryos in vitro. The degree of improvement was more pronounced when the co-culture started at an earlier stage.

Blastocyst

Intra-operative blood loss during elective lower segment caesarean section.

OBJECTIVE: To measure intra-operative blood loss at elective lower segment caesarean section and to compare estimated with measured blood loss. DESIGN: Prospective observational study. Blood loss was measured in patients who underwent lower segment caesarean section in the course of routine hospital activity. SETTING: Tsan Yuk Hospital (Hong Kong), which is affiliated to the University of Hong Kong, 1990-1991. SUBJECTS: Forty women (mean age 29 years) with singleton pregnancies (mean gestation 38 weeks) delivered by elective lower segment caesarean section under general anaesthesia (mean birthweight 3177 g). MAIN OUTCOME MEASURE: Intra-operative blood loss measured by the alkaline haematin method (intra-assay co-efficient of variation 2.2%). RESULTS: The mean measured blood loss was 487 ml (SE 40, range 164-1438). The mean estimated blood loss was 425 ml (SE 31) range 100-1300; mode 400). Observer error in estimating blood loss was higher if measured blood loss greater than 600 ml. One patient received a blood transfusion and another had a post-operative haemoglobin level less than 10.0 g/dl. CONCLUSION: Blood loss at elective lower segment caesarean section was usually less than 500 ml and was estimated with reasonable accuracy. However, there was a tendency to under-estimate blood loss when the measured loss exceeded 600 ml.

Adult

Role of single amino acids in the recognition of a T cell epitope.

T cell epitopes can be defined by the use of synthetic peptides, which when added to APC efficiently mimic naturally processed Ag. Free peptide is thought to bind to cell-surface MHC glycoproteins and the TCR then recognizes the resulting complex. The specificity of a tetanus toxin-specific human Th cell clone was investigated using a complete replacement set of peptides in which every amino acid within the minimal T cell epitope was replaced by each of the 19 alternative genetically coded amino acids. Within the minimal epitope, found to be YSYFPSVI (tetanus toxin 593-600), a small number of substitutions could be made without significant loss of activity, defined as substitutions giving peptides whose activity fell within +/- 3 SD of the mean parent response. Y593 could be substituted with F, W, M, L, V, and I; S594 with G and T; Y595, F596, and P597 with no other amino acids; S598 with A; V599 with S, and I600 with L. Rank ordering of the substitutions allowed a precise description to be made of MHC and/or TCR interaction with each amino acid side chain within the epitope. Simplified theoretic calculations based on this study indicate that class II T cell recognition has a specificity greater than 1 in 10(8). Competition experiments indicate that Y595, F596, P597, and I600 are critical for binding of this epitope to its restricting element, HLA DR4Dw14.

Amino Acid Sequence

Lymphocyte subsets in patients with oestrogen deficiency.

We have previously shown that in patients with idiopathic premature ovarian failure there were significant changes in lymphocyte subsets. To test our hypothesis that these changes were due to oestrogen deficiency we studied lymphocyte subsets in patients with oestrogen deficiency due to other causes. Blood was taken for serum oestradiol, lymphocyte counts and lymphocyte subset counts (CD2+, CD4+, CD8+ and B cells) before oestrogen replacement in 19 patients with gonadal dysgenesis, 22 patients with hypothalamic-pituitary failure and 24 healthy female control subjects. The CD4:CD8 ratio in both groups of patients was significantly lower than that in the normal control subjects while the percentages and counts of lymphocytes and CD8+ cells were significantly higher. There was a significant positive correlation between the serum oestradiol level and the CD4:CD8 ratio. These findings support the hypothesis that the changes in lymphocyte subsets are due to oestrogen deficiency.

Antigens, CD

Identification of two promiscuous T cell epitopes from tetanus toxin.

Tetanus toxoid-specific T cell clones were isolated from a human donor. To determine the T cell epitopes recognized by the clones, 30 peptides representing amphipathic alpha helical regions of the tetanus toxin were screened for ability to induce proliferation of the clones. Two T epitopes were identified. These occurred within peptides 12 and 21, and had the amino acid sequences NSVDDALINSTKIYSYFPSV and PGINGKAIHLVNNESSE, respectively. An unusual feature was that both peptides could be presented to their respective T cell clones by antigen-presenting cells of many HLA specificities. Further investigation of peptide 12 showed that the epitope was only seven amino acids in length and had a very hydrophobic sequence, namely YSYFPSV. The ability of the T cell epitope-containing peptides 12 and 21 to interact with many different HLA alleles means they may potentially be very useful as "universal carrier molecules" in synthetic vaccines.

Amino Acid Sequence

A controlled trial of bestatin in hydatidiform mole.

A prospective randomized controlled trial was conducted to study whether Bestatin, an immunomodifier, can reduce the incidence of persistent gestational trophoblastic disease in patients with hydatidiform mole. A group of 21 patients (Bestatin group) received 30 mg Bestatin daily after evacuation of the hydatidiform mole. A second group of 23 patients (control group) did not receive any drug. Blood was taken for white cell counts, differential counts, lymphocyte subset counts (CD2+, CD4+, CD8+ and B cells) and natural killer cell activity before evacuation of the hydatidiform moles. The tests were repeated every 4 weeks after evacuation until the serum beta subunit of human chorionic gonadotropin (beta hCG) had returned to normal or until the patient had to receive chemotherapy because of persistent gestational trophoblastic disease. There was no significant difference in the age of the patients, the pre-evacuation serum beta hCG, or the gestational age between the two groups. Chemotherapy was needed by 6 patients in the Bestatin group (28.6%) and 3 patients in the control group (13%) because of persistent gestational trophoblastic disease. There was no significant difference in any of the immunological parameters between the two groups before or after evacuation. We conclude that Bestatin at this dosage does not improve the immunological functions or clinical outcome in patients with hydatidiform mole.

Adjuvants, Immunologic

Serum lipids in Chinese patients using oral contraceptive pills.

Eighty-four Chinese patients attending the Family Planning Association of Hong Kong for contraception with oral contraceptive pills were randomized into 2 groups. The first group received pills containing 0.15 mg levonorgestrel and 0.03 mg ethinyl oestradiol. The second group received pills containing 0.15 mg desogestrel and 0.03 mg ethinyl oestradiol. Blood was taken after overnight fast before the use of pills for assay of serum total lipids, triglycerides, total cholesterol and high density lipoprotein cholesterol (HDL-C). The tests were repeated at 1 month, 3 months and 6 months after the use of pills. There was a significant increase in the serum total lipids in the levonorgestrel group but not in the desogestrel group. The serum triglycerides showed a significant increase in the desogestrel group but not in the levonorgestrel group. There was no significant change in the serum total cholesterol levels in both groups. There was a significant decrease in the HDL-C in the levonorgestrel group but there was no significant change in the desogestrel group.

Adult

Differential evaluation of human sperm hypoosmotic swelling test and its relationship with the outcome of in-vitro fertilization of human oocytes.

The hypoosmotic swelling test is a simple laboratory test to measure the functional integrity of the human sperm membrane. Its in-vivo and in-vitro applicability needs to be evaluated before it can be accepted as a useful routine test for the fertilizing potential of human semen. We studied the standard semen analysis results and differential sperm tail swelling patterns of seminal and swim-up sperm after hypoosmotic treatment in 97 semen samples used for in-vitro fertilization of human oocytes. Semen samples were classified as infertile (0% fertilization rate; n = 27) or fertile (greater than 0% fertilization rate; n = 70) before statistical analyses. There was a significant difference (P less than 0.005) in percentage normal morphology of seminal sperm between the fertile and infertile semen samples. The percentage normal morphology of seminal sperm correlated (r = 0.4250; P less than 0.005) with the in-vitro fertilization rate of human oocytes and this parameter was selected by the multivariate stepwise discriminant analysis as the discriminator capable of predicting the in-vitro fertilization rate with 57.7% accuracy. The percentage total swelling of seminal and swim-up sperm after hypoosmotic treatment was not correlated with the in-vitro fertilization rate. The percentage swelling pattern g (the open type) of seminal sperm was also selected by the multivariate stepwise discriminant analysis as the discriminator to predict the in-vitro fertilization rate. This parameter correlated with the percentage normal morphology of seminal sperm (r = 0.3014; P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Cell Membrane

Prevalence of cataract among the institutionalized elderly in Hong Kong.

The Hong Kong 1981 Census found a high prevalence of blindness in the age group aged 65 and above. Visual defects short of blindness are also a special problem among the elderly and cataract is one of the most important causes. We have studied the prevalence of cataract among 546 subjects living in homes or hostels for the aged in a New Town in Hong Kong. Cataract was defined as having a lens opacity and visual acuity worse than 20/100 in either eye. A prevalence of 45% among men and 32% among women was found. There was significant difference in prevalence between men and women aged below 75 but little sex difference was noted for the older age groups. Among the cataract cases detected on screening, about half had not had the diagnosis made previously. The results confirm the need for more epidemiological and health care studies on the visual problems among the aged.

Aged

Analysis of human T cell response to two Plasmodium falciparum merozoite surface antigens.

Eight novel human T cell epitopes were identified within the two major merozoite surface antigens (MSA1 and MSA2) of Plasmodium falciparum using synthetic peptides. All except one of the peptides conformed structurally to an amphipathic alpha helix and three out of the four MSA1 peptides also contained sequences containing the Rothbard motif. Peptide MSA2/2, which fitted none of these criteria, was recognized by our donors to a similar degree as the other peptides. This peptide also contains a B cell epitope. Proliferative responses were obtained in both immune and nonimmune donors, however, the number of responses in the immune donor group was significantly higher. There was no correlation between the level of proliferation and antibody titers to these antigens. No peptides were preferentially recognized in association with specific HLA class II antigens.

Animals

Predictive value of sperm morphology and movement characteristics in the outcome of in vitro fertilization of human oocytes.

One hundred fourteen semen samples from Chinese males were analyzed for routine semen parameters including the semen volume, sperm count, percentage motility, and percentage normal morphology. Of these 114 samples, 54 also had movement characteristics of seminal and swim-up sperm evaluated by the computer image analyzer system (Cellsoft; Cryo Resources Co., New York). All semen samples were subjected to the swim-up procedure to harvest the motile sperm before inseminations of human oocytes. Fertilization was considered to have occurred when at least one oocyte was observed with two or more pronuclei. Semen samples were classified as infertile (0% fertilization rate; N = 32) or fertile (greater than 0% fertilization rate; N = 82) before statistical analyses. There was a significant difference (P less than 0.005) in percentage normal morphology of seminal sperm between the fertile (mean +/- SE; 67.3 +/- 1.2%) and the infertile (59.3 +/- 2.2%) samples. The percentage normal morphology of seminal sperm correlated (r = 0.3049; P less than 0.002) with the fertilization rate and this parameter was selected by the multivariate stepwise discriminant analysis as the discriminator capable of predicting the fertilization rate with 57.9% accuracy. Statistical analyses of samples where sperm movement was also evaluated demonstrated that there was significant differences (P less than 0.01) between the fertile (N = 38) and the infertile (N = 16) samples in percentage normal morphology of seminal sperm (67.8 +/- 1.8% vs 56.2 +/- 2.6%) and curvilinear velocity of swim-up sperm (89.2 +/- 3.5 vs 68.2 +/- 7.2 microns/sec).(ABSTRACT TRUNCATED AT 250 WORDS)

Female

Efficacy of the urinary hemagglutination test (Higonavis) and enzyme immunoassay (Ovustick) in detection of the spontaneous luteinizing hormone surge in an in vitro fertilization/gamete intrafallopian transfer (IVF/GIFT) program.

Fifty-eight treatment cycles in an in vitro fertilization/gamete intrafallopian transfer (IVF/GIFT) program were studied to compare the efficacy of two urinary methods, hemagglutination test (Higonavis) and enzyme immunoassay (Ovustick), in detection of spontaneous luteinizing hormone (LH) surge. If an isolated rise in urinary LH level was taken as indicative of LH surge, the false-positive rate was 36.7% for Higonavis and 10.2% for Ovustick. The difference was statistically significant (P less than 0.001). If only a sustained rise in urinary LH was taken to indicate LH surge, the false-positive rate was 6.1% for Higonavis and 0% for Ovustick. In the seven cycles with a spontaneous plasma LH surge, there was a positive correlation between the plasma LH levels and the two urinary assay methods in six cycles (85.7%). Compared to plasma LH, there was a mean delay of 17.4 hr by the Higonavis test and 15.6 hr by the Ovustick test. If a sustained rise in urinary LH levels was taken as indicative of LH surge, both methods are quite accurate but the Ovustick appeared to be more specific.

Evaluation Studies as Topic

Intrauterine insemination is not useful in oligoasthenospermia.

A prospective randomized study was conducted in 47 couples with infertility due to subnormal semen to compare luteinizing hormone (LH)-timed intrauterine insemination with LH-timed natural intercourse. No pregnancy occurred in 114 cycles of intrauterine insemination with washed sperm. Only one patient conceived during 1 of the 124 natural intercourse cycles. The only complication that occurred after intrauterine insemination was mild abdominal cramp in 3 cycles. The authors conclude that intrauterine insemination is not useful in the management of subfertility due to oligoasthenospermia.

Adult