Search PubMed⌕ Search

Biomedical subjects

P C Ho

Publications and source records attributed to P C Ho.

At least 37 records · Page 2Linked to original sources
PubMed2004

Intracervical sodium nitroprusside versus vaginal misoprostol in first trimester surgical termination of pregnancy: a randomized double-blinded controlled trial.

BACKGROUND: Results from small-scale randomized studies on the effectiveness of different preparations of nitric oxide donors in cervical priming before first trimester termination of pregnancies are not consistent. We compared sodium nitroprusside gel to misoprostol, the standard agent for cervical priming in this randomized double-blinded controlled trial. METHODS: Two hundred pregnant patients between 8 to 12 weeks admitted for surgical termination of pregnancy were recruited. They were randomized into either 400 microg vaginal misoprostol and intracervical placebo gel, or 10 mg intracervical sodium nitroprusside gel and placebo tablets 3 h before the procedure. The baseline cervical dilatation and cumulative force required to dilate the cervix from 4 to 9 mm were measured with a tonometer. Blood pressure was measured and side effects were assessed. RESULTS: The cumulative force to dilate the cervix from 4 to 9 mm was significantly higher in the sodium nitroprusside group, and the difference remained when a sub-group analysis was performed according to parity. Baseline cervical dilatation, duration of operation and operative blood loss were all in favour of misoprostol. Transient drop in blood pressure was observed after sodium nitroprusside treatment. CONCLUSIONS: Intracervical sodium nitroprusside is not as effective as misoprostol in cervical priming.

Abortifacient Agents, Nonsteroidal↗
PubMed2004

Imaging cells and tissues with refractive index radiology.

Can individual cells, including live cells, be imaged using hard x rays? Common wisdom until now required sophisticated staining techniques for this task. We show instead that individual cells and cell details can be detected in culture solution and tissues with no staining and no other contrast-enhancing preparation. The sample examined can be much thicker than for many other microscopy techniques without sacrificing the capability to resolve cells. The key factor in our approach is the use of a coherent synchrotron source and of contrast mechanisms based on the refractive index. The first successful tests were conducted on a variety of cell systems including skin and internal leaf cells, mouse neurons, rabbit fibroblast cells, and human tumor cells.

Animals↗
PubMed2004

Effect of advanced provision of emergency contraception on women's contraceptive behaviour: a randomized controlled trial.

BACKGROUND: Emergency contraception (EC) can prevent pregnancy but is under-used. Advanced provision increases use but the effect on contraceptive behaviour varies. METHODS: Women aged 18-45 years, using less effective contraceptives, were randomized to either advanced provision of three courses of EC (intervention) or to obtaining each course from clinic (control). EC use and contraceptive behaviour were monitored for 1 year. RESULTS: In all, 1030 women were recruited in 6 months. The mean+/-SD number of courses of EC used in intervention versus control group was 0.56+/-1.2 versus 0.20+/-0.6 (P<0.001). In the intervention group, 47% women aged <26 years used at least one course of EC compared with 23% of older women (P<0.001). The majority of women used condoms before (intervention 89%, control 91%) and during the study (89% for both groups). Consistency of contraceptive use was higher during the study (65 versus 60% of women in both groups) (P<0.001). There were 17 unplanned pregnancies, eight in the intervention group, six of whom did not use EC in the conception cycle. CONCLUSIONS: Advanced provision increases EC use especially among young women in Hong Kong. Contraceptive choice and consistency of use remains the same even among young women.

Adult↗
PubMed2004

Establishment of a capillary-cumulus model to study the selection of sperm for fertilization by the cumulus oophorus.

BACKGROUND: Spermatozoa have to traverse the cumulus oophorus before fertilization in vivo. Evidence suggests that the cumulus oophorus plays an important role in the fertilization process. We describe the establishment of a capillary-cumulus oophorus model with which to study the action of cumulus mass on the function of human spermatozoa. METHODS: Human cumulus oophorus was aspirated into a glass capillary. Spermatozoa were allowed to pass through the cumulus mass in the capillary from one end of the capillary. The spermatozoa that had traversed the mass were collected at the other end of the capillary and underwent sperm function analyses. RESULTS: Compared with those spermatozoa cultured in medium alone, spermatozoa exposed to the cumulus mass were more likely to have normal morphology, be capacitated and acrosome reacted, with a distinct motility pattern and better zona-binding capacity. CONCLUSION: A novel in vitro model for spermatozoa penetration through the cumulus oophorus was established. The model can be applied to investigate the effect of the cumulus oophorus on sperm functions.

Acrosome Reaction↗
PubMed2004

A pilot-randomized comparison of sublingual misoprostol with syntometrine on the blood loss in third stage of labor.

BACKGROUND: To compare sublingual misoprostol with intravenous syntometrine use during third stage of labor by measuring the blood loss. METHODS: Sixty women were randomized to receive either 600 micro g misoprostol sublingually or 1 ml syntometrine intravenously during the third stage of labor after spontaneous vaginal delivery. For those with risk factors of postpartum hemorrhage such as medical induction or augmentation of labor, previous third stage complications were excluded. The blood loss in labor was measured by the alkaline-hematin method, and differences in hemoglobin before and after delivery were compared. RESULTS: There was no significant difference in the median measured blood loss between the misoprostol group and the syntometrine group (280 versus 226 ml, p = 0.45). The change in hemoglobin was comparable between the two groups. There were more women in the misoprostol group who required additional oxytocics, but the difference was not statistically significant. A major complication occurred in one patient in the misoprostol group with blood loss in excess of 1000 ml. The incidence of side effects such as shivering and pyrexia in women receiving misoprostol was significantly higher than that in the syntometrine group. CONCLUSION: The use of sublingual misoprostol or intravenous syntometrine in spontaneous vaginal delivery resulted in a comparable amount of blood loss. Transient side effect such as fever and shivering which resolved within a day occurred more frequent to those who received sublingual misoprostol.

Administration, Sublingual↗
PubMed2004

Ultrasound for the detection of vegetative foreign body in hand--a case report.

Foreign bodies in soft tissues are commonly encountered in daily orthopaedic practice. While most of the metals and glass foreign bodies can be detected by plain radiograph, organic substances such as wood and vegetative materials are radiolucent. Unfortunately, these radiolucent foreign bodies are usually more prone to cause an inflammatory reaction and infection. The detection can be even more difficult in cases of multiple foreign bodies and in penetrating injuries with small innocuous skin wounds. Ultrasonography is a sensitive and reliable investigation for detection of foreign bodies in soft tissue. We present a case of penetration injury to thumb with residual radiolucent foreign bodies and demonstrate the proper role of ultrasonography in the management of foreign bodies in soft tissues.

Adult↗
PubMed2004

Suicidal mercury injection into the upper limb: a case study.

We report a rare case of self-injection of mercury into the subcutaneous tissue of the upper limb. A multi-disciplinary management approach was adopted including cooperation between toxicologists, orthopaedic surgeons, radiologists and environment safety personnel. Surgical removal of mercury under radiological screening and systemic intoxication treated by chelating agents, namely dimercaprol and succimer. Serial serum and urine mercury levels showed an initial rise despite surgical removal and returned to normal after a prolonged period of time. Safety precautions were taken during surgery to avoid inadvertent intoxication of staff. Contamination of the operation theatre was monitored by the amount of mercury vapour released into the air. All personnels involved in the management of the patient did not show any evidence of mercury intoxication.

Adult↗
PubMed2003

Quantitation of paclitaxel in micro-sample rat plasma by a sensitive reversed-phase HPLC assay.

A sensitive high-performance liquid chromatographic (HPLC) method was developed for the determination of paclitaxel in micro-samples of rat plasma in order to study the mechanism of enhanced systemic exposure of paclitaxel co-administered with P-glycoprotein inhibitors. The assay involved solid-phase extraction procedures using 2'-methylpaclitaxel as the internal standard. Chromatographic separations were achieved using a ZORBAX ODS C18 column and mobile phase consisting of acetonitrile, methanol and ammonium acetate buffer (10 mM, pH 5.0) (48.5:16.5:35) pumped at 0.8 ml/min. The effluents were measured for UV absorption at 227 nm, with retention times of 8.5 and 11.0 min for paclitaxel and 2'-methylpaclitaxel, respectively. The chromatographic separation was excellent, with no endogenous interference. The standard curves showed a good linearity (r=0.9994) over the concentration ranges of 10-1,000 ng/ml. At 1,000 ng/ml, the absolute recoveries of paclitaxel and 2'-methylpaclitaxel are 89 and 90%, respectively. The intra- and inter-day variabilities of paclitaxel were both less than 15%. This validated method for the assay of paclitaxel in micro-sample rat plasma made it feasible to study the pharmacokinetics of the drug in a single rat.

Animals↗
PubMed2003

Amniotic fluid human chorionic gonadotrophin and alpha-fetoprotein levels in pregnancies conceived after assisted reproduction.

OBJECTIVES: To study the alteration in the second-trimester maternal serum levels of human chorionic gonadotrophin (hCG) and alpha-fetoprotein (AFP) in pregnancies conceived after assisted reproduction. METHODS: We compared the amniotic fluid hCG and AFP concentrations of 45 pregnancies with fresh embryo transfer and 25 pregnancies with frozen-thawed embryo transfer with 269 spontaneous pregnancies. Wilcoxon rank-sum test was used for analysis. RESULTS: The median amniotic fluid hCG MoM in pregnancies conceived after frozen-thawed embryo transfer was significantly increased to 1.41 compared to 1.00 (p = 0.01) in naturally occurring pregnancies and 0.96 (p = 0.049) in pregnancies after fresh embryo transfer. Further analysis showed that this was only observed in frozen embryos fertilized by conventional insemination with MoM of 1.59. The AFP MoMs were similar among the groups. CONCLUSIONS: The observed raised amniotic fluid hCG level in IVF-FET pregnancies may reflect the elevated maternal serum level in these pregnancies. Further studies should be directed towards exploring the underlying pathophysiology.

Adult↗
PubMed2003

Amenorrhea associated with contraception-an international study on acceptability.

Surveys undertaken in the 1970s and 1980s suggested that amenorrhea was unacceptable to most women, especially in developing countries. More recent research suggests that increasing numbers of women in the developed world prefer to menstruate less often. In a questionnaire survey of 1001 women attending family-planning clinics and 290 contraceptive providers in China, South Africa, Nigeria and Scotland, only among black women in Africa did the majority like having periods. In all other groups, most women disliked periods, which were "inconvenient" and associated with menstrual problems. Given the choice, the majority of Nigerian women would prefer to bleed monthly. Elsewhere, women would opt to bleed only once every 3 months, or not at all. In all except the Chinese centers, the majority of women would be willing to try a contraceptive which induced amenorrhea. Providers tended to overestimate the importance of regular menstruation to their clients. This is an important observation for scientists and funding agencies involved in developing new methods of contraception.

Adult↗
PubMed2003

A comparison of isosorbide mononitrate and misoprostol cervical ripening before suction evacuation.

OBJECTIVE: To compare the efficacy of a nitric oxide donor (isosorbide mononitrate) and a prostaglandin E1 analogue (misoprostol) for cervical priming before suction termination of pregnancy. METHODS: This was a randomized, double blind, placebo-controlled trial. One hundred twenty-six healthy women requesting termination of pregnancy between 9 and 12 weeks' gestation were recruited. Women were randomized into three groups: control, isosorbide mononitrate, and misoprostol. All women were given moistened intravaginal study drugs (placebo, 40 mg of isosorbide mononitrate, or 400 microg of misoprostol) 4-6 hours before suction evacuation. Side effects were assessed 3 hours after drug administration. The cervical dilatation and the cumulative force required to dilate the cervix to 8 mm were measured by a cervical tonometer before suction evacuation. Operative blood loss was measured after sieving off the products of gestation. RESULTS: There were no differences in the baseline cervical dilatation, cumulative force, and operative blood loss between the isosorbide mononitrate and placebo groups. However, women in the misoprostol group had a significantly greater cervical dilatation, required less cumulative force, and had less blood loss than women in the isosorbide mononitrate or control group. The majority (more than 80%) of women in all three groups found their cervical priming agents acceptable. CONCLUSION: Intravaginal isosorbide mononitrate was less effective than misoprostol in cervical ripening before suction termination of pregnancy.

Abortion, Induced↗
PubMed2003

Enhanced localization of osteoid osteoma with radiolabeling and intraoperative gamma counter guidance: a case report.

Osteoid osteoma is a benign bone tumor that can be removed by marginal excision. Excessive removal of reactive bone may result in significant morbidity. We made use of the highly specific radioactive technetium uptake characteristic of osteoid osteoma for its localization. Radioactive technetium (25 mCi) was injected intravenously 2 hours before surgery to a 21-year-old male patient with an osteoid osteoma over the left distal radius. Tumor tissue was localized intraoperatively by a portable hand-held radioactive gamma counter to detect a focal high intensity of radioactivity. Complete tumor removal was shown by reduction of radioactivity to background level. This was confirmed by bone scintigraphy of the specimen and the forearm immediately after surgery. The defect was packed with cancellous bone graft taken from the ipsilateral distal radius through the same wound. Postoperative recovery was very satisfactory. We found this approach useful in limiting resection margin and surgical site morbidity in resection of osteoid osteoma.

Adult↗
PubMed2003

Molecular analysis of the androgen receptor gene in Hong Kong Chinese infertile men.

PURPOSE: To investigate the relationship between CAG repeat length in the androgen receptor gene and impaired spermatogenesis in Hong Kong Chinese population. METHODS: The CAG repeat region was amplified by polymerase chain reaction (PCR) in 85 nonobstructive azoospermic or severe oligozoospermic men, and 45 fertile males. The number of CAG repeat was analyzed by DNA sequencing. Serum FSH, LH, and testosterone levels were also determined in these men. RESULTS: Among nonobstructive azoospermic males, three men (5.7%) possessed short CAG repeats (< 16), and three (5.7%) other men possessed long CAG repeats (> 30). Short CAG repeats (< 16) were also found in two severe oligozoospermic males (6.3%). The incidence of infertile men with short or long CAG repeats is significantly higher in the azoospermic group (p = 0.03) but not in the severe oligozoospermic group (p = 0.17) when compared with the fertile controls CONCLUSION: Our data suggest an association between CAG repeat lengths and impaired spermatogenesis in azoospermic males in our population.

Adolescent↗
PubMed2003

Influence of CYP2C9 genotypes on the formation of a hepatotoxic metabolite of valproic acid in human liver microsomes.

The present study investigated the effect of cytochrome P450 2C9 (CYP2C9) genetic polymorphism on the biotransformation of valproic acid (VPA) to its hepatotoxic metabolite, 4-ene-VPA, and compared that to the formation of the inactive 4-OH-VPA and 5-OH-VPA. cDNA-expressed CYP2C9(*)2 and CYP2C9(*)3 variants were less efficient than the CYP2C9(*)1 wild type in catalyzing the formation of these metabolites, as assessed by the ratio of Vmax and apparent Km (in vitro intrinsic clearance). The reduced efficiency by CYP2C9(*)2 was due to a reduced Vmax, whereas, in the case of CYP2C9(*)3, it was the result of increased apparent Km. The formation rates of 4-ene-VPA, 4-OH-VPA, and 5-OH-VPA in human liver microsomes were reduced by 29, 28, and 31%, respectively, in samples with one mutated CYP2C9 allele, and by 61, 73, and 58%, respectively, in samples with two mutated CYP2C9 alleles. Overall, the homozygote and heterozygote CYP2C9(*)2 and CYP2C9(*)3 genotypes may compromise hepatic VPA biotransformation.

Analysis of Variance↗
PubMed2003

Stability of extemporaneously prepared saquinavir formulations.

AIMS: The effects of pH and excipients on the stability of saquinavir in extemporaneously prepared suspensions were assessed. The stability of a developed extemporaneously prepared saquinavir suspension was then determined at 5 and 25 degrees C over 30 days. METHOD: Extemporaneous saquinavir 2 mg/mL formulations were prepared from soft gelatin capsule (Fortovase). Four batches of the formulations were buffered at pHs 2, 4, 5 and 7, whereas the other five batches were prepared in Milli-Q water, 0.5% (w/v) citric acid, 0.1% (w/v) sodium ascorbate, 10% (v/v) syrup and in vehicle containing both 0.5% (w/v) citric acid and 0.1% (w/v) sodium ascorbate. The stability of these formulations was tested at 25 degrees C. A final formulation of saquinavir suspension (60 mg/mL) containing both 10% (v/v) syrup and 0.5% (w/v) citric acid was developed and tested for stability at 5 and 25 degrees C for up to 30 days using a stability-indicating high-performance liquid chromatographic method. RESULTS: Saquinavir was most stable at pH 2-4. Formulations containing sodium ascorbate, citric acid and syrup or both citric acid and sodium ascorbate were significantly more stable than the control formulation (saquinavir 2 mg/mL in Milli-Q water). CONCLUSION: The pH for optimal stability of saquinavir was around 2-4. Besides pH adjustment, saquinavir could also be stabilized by adding anti-oxidants. The saquinavir 60 mg/mL formulation prepared with about a pH of about 4 was stable at both 5 and 25 degrees C for at least 30 days.

Capsules↗
PubMed2003

Maternal serum hCG and alpha-fetoprotein levels in pregnancies conceived after IVF or ICSI with fresh and frozen-thawed embryos.

BACKGROUND: Studies have shown that levels of serum markers of Down's syndrome were altered in pregnancies conceived after IVF, though the reason for this remains unknown. METHODS: Second-trimester maternal serum levels of hCG and alpha-fetoprotein (AFP) in pregnancies conceived with fresh and frozen-thawed embryos after assisted reproduction were compared with those conceived spontaneously. RESULTS: There were 203 pregnancies with fresh embryo transfers (130 IVF cases, 73 ICSI cases) and 98 pregnancies with frozen-thawed embryo transfers (61 IVF cases, 37 ICSI cases). The controls consisted of 17 145 spontaneous pregnancies. The median hCG multiples of the median (MoM) was significantly increased to 1.24 in 98 pregnancies conceived after frozen embryo transfer. This elevation was observed only in the IVF-frozen embryo transfer subgroup (P < 0.001), but not in the ICSI-frozen embryo transfer subgroup. The median AFP MoM for 203 pregnancies after fresh embryo transfer was 0.90. Among the subgroups, the median AFP MoM was significantly reduced to 0.90 and 0.86 in IVF-embryo transfer (P = 0.04) and ICSI-embryo transfer (P = 0.001) pregnancies respectively, and significantly raised to 1.20 in the IVF-frozen embryo transfer subgroup. CONCLUSIONS: The degree of alterations in maternal serum hCG and AFP levels varied between fresh and frozen-thawed embryos, and also between the mode of fertilization. Pregnancies resulting from ICSI or frozen embryo transfer should be regarded as distinct entities from those of IVF-embryo transfer.

Case-Control Studies↗