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Biomedical subjects

C D Chen

Publications and source records attributed to C D Chen.

53 records · Page 3Linked to original sources
PubMed1996

How many embryos should be transferred in in vitro fertilization and tubal embryo transfer?

In order to achieve higher pregnancy rates, more than one embryo is usually transferred in in vitro fertilization (IVF) programs. Tubal embryo transfer (TET) produces an even higher pregnancy rate. However, the number of embryos that should be transferred in TET programs remains to be clarified. We studied a series of 241 consecutive TET cycles and analyzed their clinical characteristics, embryo numbers, cumulative embryo score (CES), and pregnancy outcomes. The results demonstrated that 1) four embryos was an adequate number to obtain a satisfactory pregnancy rate and fewer multiple pregnancies, 2) older patients and cases with male factor had less chance of pregnancy and more than four embryos could be transferred, and 3) CES values > 40 were preferred, but for young patients with unusually high anxiety about multiple pregnancies, a CES of 21 to 40 was optimal. A policy of transfer that limits transfer to a maximum of two, three or four embryos is not suitable in all cases and other factors (eg, repeated IVF failure or older age) should be individually considered. Therefore, two equations utilizing CES, age and failure of previous TET as the factors were developed to help practitioners to evaluate how many embryos should be transferred on an individual basis.

Adult↗
PubMed1996

Borderline malignant tumors of the ovary: study of prognostic factors.

A 16-year review of borderline tumors of the ovary was carried out to study the clinical features and outcomes of patients and to assess the value of color Doppler ultrasound in preoperative diagnosis. The records of 53 patients with borderline tumors of the ovary were retrospectively analyzed for clinical features, sonographic findings and survival. Twenty-three of 44 patients with stage I disease were treated conservatively without recurrence. Seven of eight (87.5%) patients with stage III disease developed recurrent or persistent tumors within 3 years. Overall, eight of 53 (15.1%) patients had recurrent or persistent disease. Twenty-three of 44 (52.3%) patients with borderline ovarian tumors showed morphologic malignancy by gray-scale sonography. Ten of 13 (76.9%) patients who had color Doppler ultrasound examination had detectable intratumoral blood flow. The mean resistance index value was 0.47 (range, 0.3-0.6). Three of these patients (30%) had a resistance index value < 0.4. The results indicated that the extent of disease as reflected by the clinical stage was the main factor for prediction of recurrence, and borderline tumors of the ovary were not efficiently differentiated from benign or malignant tumors by resistance index values obtained from color Doppler ultrasound.

Adolescent↗
PubMed1996

Aberrant crypts as a biomarker for colon cancer: evaluation of potential chemopreventive agents in the rat.

We assessed the effects of 41 potential chemopreventive agents in the F344 rat using the inhibition of carcinogen-induced aberrant crypt foci (ACF) in the colon as the measure of efficacy. ACF were induced by the carcinogen azoxymethane in F344 rats by two sequential weekly injections at a dose of 15 mg/kg. Two weeks after the last azoxymethane injection, animals were evaluated for the number of aberrant crypts detected in methylene blue-stained whole mounts of rat colon. The 41 agents were derived from a priority listing that was based on reports of chemopreventive activity in the literature and/or efficacy data from in vitro models of carcinogenesis. The list of agents included representative examples of phytochemicals, vitamins, minerals, inhibitors of proliferation, inducers of Phase 1 and Phase 2 metabolism systems, nonsteroidal anti-inflammatory agents, and differentiation agents. Eighteen agents were positive in the assay, significantly reducing the incidence of ACF at least in one of two doses tested. As a chemical class, the nonsteroidal anti-inflammatory drugs, which included ibuprofen, ketoprofen, piroxicam, and indomethacin, were most active; other less potent agents were arginine, butylated hydroxyanisole, curcumin, diallyl sulfide, difluoromethylornithine, 18 beta-glycyrrhetinic acid, indole-3-carbinol, oltipraz, purpurin, rutin, and the sodium salts of butyrate, selenite, and thiosulfate. Twenty-three agents did not inhibit ACF; included among these were several agents that promoted the development of ACF at one or both doses tested: benzyl isothiocyanate,calcium glucarate, catechin, dihydroepiandosterone, fluocinolone acetonide,folic acid, levamisole, 2-mercaptoethanesulfonic acid, nordihydroguiaretic acid, potassium glucarate, propyl gallate, beta-sitosterol, sodium cromolyn, sodium molybdate, and sulfasalazine. The aberrant crypt assay demonstrates reasonable specificity and sensitivity in predicting which agents are likely to prevent colon cancer.

Animals↗
PubMed1995

The cytoplasmic and N-terminal transmembrane domains of cytochrome P450 contain independent signals for retention in the endoplasmic reticulum.

Microsomal cytochrome P450 is inserted into the membrane of the endoplasmic reticulum (ER) by its N-terminal signal/anchor sequence which also functions as an ER retention signal. To analyze further potential retention signals of cytochrome P450, topological domains of cytochrome P450 2C1 or 2C2, epidermal growth factor receptor, a plasma membrane protein, and bacterial alkaline phosphatase, a secreted protein were exchanged. The N-terminal signal/anchor of cytochrome P450 2C1 functioned as an ER retention signal when placed at the N terminus of several reporter proteins but not when fused at the C terminus of the extracellular domain of epidermal growth factor receptor, with or without a heterologous cytoplasmic domain. Chimeric proteins in which the cytoplasmic domain of cytochrome P450 2C2 was substituted for that of epidermal growth factor receptor were retained in the ER indicating that an independent retention signal is present in the cytoplasmic part of cytochrome P450 2C2. These chimeras were enzymatically active which argues against misfolding as the primary cause of retention. The ER retention signal of the cytoplasmic domain could not be localized to a single amino acid segment by deletion analysis. These results show that cytochrome P450 2C2 contains redundant, complex ER retention signals in its cytoplasmic and N-terminal hydrophobic domains and that the function of the N-terminal signal is context-dependent.

Alkaline Phosphatase↗
PubMed1995

Inhibition of aberrant crypt growth by non-steroidal anti-inflammatory agents and differentiation agents in the rat colon.

Aberrant crypts are aggregates of single to multiple colonic crypts evidencing hallmarks of dysplasia and may be the earliest detectable pathological lesions for colon cancer. The aberrant crypt assay has been developed in 2 protocols. In one, putative chemoprevention agents are tested for inhibitory effects when administered concomitantly with a carcinogen. In the other, the objective of this study, aberrant crypts were induced in F344 rats by parenteral injection of the colon carcinogen azoxymethane (AOM) and allowed to develop for 4 weeks, when an average of 90-100 aberrant crypt foci per colon were found in the methylene blue-stained colon. Then, during the second 4 weeks of the experiment, aberrant crypts were allowed to further develop to a frequency of > 150 foci per colon, a time when multi-crypt foci were observed. During this time we tested the inhibitory effects of 4 analgesic drugs and 2 differentiation agents for effects of aberrant crypt growth and development. We found the non-steroidal anti-inflammatory drugs piroxicam, aspirin and ibuprofen, but not acetaminophen, to be effective in suppressing aberrant crypt formation or the progression to foci of multiple aberrant crypts. Treatment with chemosuppressing agents 13-cis-retinoic acid (13-cRA) and 4-hydroxyphenretinamide (4-HPR), known differentiating agents, however, did suppress expansion of aberrant crypt foci, with 13-cRA being the much more potent agent.

Acetaminophen↗
PubMed1995

Is total abdominal hysterectomy with bilateral salpingo-oophorectomy adequate for new FIGO stage I endometrial carcinoma?

OBJECTIVE: The new FIGO staging for endometrial cancer cases complies with other forms of surgical staging and correlates better with clinical outcomes because it includes prognostic factors. This study was done to investigate whether total abdominal hysterectomy with bilateral salpingo-oophorectomy (TAH+BSO) is adequate for new FIGO Stage I endometrial carcinoma. SUBJECTS: Sixty-five cases of endometrial carcinoma defined according to the new FIGO Stage Ia (n = 26), Ib (n = 24) and Ic (n = 15) were analysed. They all received TAH+BSO only and were followed up for at least two years. METHODS: The histologic type, grade, depth of myometrial invasion, lympho-vascular tumour emboli and tumour size were analysed by t-test to correlate the risk factors for treatment failure. RESULTS: There were no recurrences after TAH+BSO in Ia and Ib cases. However, recurrences occurred in five cases (33%) of Stage Ic with deep myometrial invasion, high histologic grade, large tumour size and tumour emboli. CONCLUSIONS: TAH+BSO is inadequate in some Ic cases with a high histologic grade, deep myometrial invasion and tumour emboli. Thus, thorough pre-operative and intra-operative staging, adequate operation method and prompt post-operative adjuvant therapy are indispensable for successful treatment.

Adult↗
PubMed1994

Intrauterine intervention in a case of recurrent meconium peritonitis.

We present a case of recurrent meconium peritonitis detected in the second trimester and treated by intrauterine intervention. Antenatal ultrasound findings included fetal ascites and intra-abdominal calcification. Aspiration of fetal ascites under ultrasound guidance and determination of the bilirubin concentration established the diagnosis of meconium peritonitis. Paracentesis was repeated to remove irritating intestinal contents and to decrease pressure on the fetal thorax. Although the exact cause of the meconium peritonitis remains unknown, the recurrence of the condition suggests a genetic basis. A possibility of cystic fibrosis was not considered because the clinical picture did not suggest it. Intrauterine intervention helped to establish the diagnosis of meconium peritonitis and may have contributed to the good outcome.

Adult↗
PubMed1993

Intrauterine death of co-twin in the third trimester: a case report of twin-to-twin transfusion syndrome and cord accident.

Intrauterine death of one twin in a monochorionic twin pregnancy is associated with increased mortality and morbidity of the survivor. The exact cause is usually difficult to determine even after delivery. The choice of management for the mother and the viable co-twin is difficult. We report on a case of intrauterine death of one twin with monochorionic placentation. Twin-to-twin transfusion syndrome was suggested by the sonographic findings and evidence of a vascular communication. The co-twin survived for another 39 days without complications after the diagnosis of fetal death. Postmortem examination showed severe torsion and constriction of the umbilical cord at the fetal end with focal deficiency of Wharton's jelly. It is likely that torsion and constriction of the cord was responsible for the one intrauterine fetal death; this so-called "twist amputation" of the cord, on the other hand, contributed to the favorable outcome in the surviving co-twin.

Adult↗
PubMed1993

[Intravenous midazolam for sedation in epidural anesthesia].

30 cases receiving epidural anesthesia for lower extremities and abdominal surgery were selected in this study. Their physical status and average age were ASA I or II and 41 +/- 10.0 years old. Premedication included intramuscular injection of pethidine, atropine and promethazine. Epidural anesthesia was accomplished with 15 ml 2% lidocaine with epinephrine (1:80,000). After the stabilization of vital signs, the patients were put asleep by 0.1 mg/kg of midazolam intravenously. They were then evaluated by the sedative, cardiovascular, respiratory and recovery effects of intravenous midazolam in epidural anesthesia. The results were as follows: The patients receiving IV midazolam averagely fell asleep in 61.6 +/- 20.5 seconds and maintained asleep for 55.4 +/- 12.7 minutes. Pain on injection was not noted in these cases. Cardiovascular parameters revealed midazolam with general depression on systolic pressure (17.4 +/- 7.3%), diastolic pressure (13.4 +/- 8.4%), mean arterial pressure (12.7 +/- 7.0%), heart rate (10.9 +/- 7.2%), stroke volume (13.7 +/- 8.9%) and cardiac output (18.4 +/- 7.0%) respectively. The peak depression reached around 10 minutes after drug administration. Respiratory parameters dropped with SaO2 (1.1 +/- 1.6%) and respiratory rate (9.7 +/- 5.7%) and fell into trough after 5 minutes of drug administration. Although all the above parameters measured were statistically significant, they were of no clinical importance that required further management. No case had delirium, anxiety and vomiting in the recovery period. Conclusively, patients receiving epidural anesthesia with supplement of intravenous midazolam provides a good sedative effect. Clinically, there was less severe untowards reaction either in cardiovascular or respiratory systems. Smooth and stable recovery was also noted.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Growth kinetics and chemoprevention of aberrant crypts in the rat colon.

Single and multiple colonic crypts exhibiting dysplasia that are detectable in situ by staining of rat colon with methylene blue are called aberrant crypts (AC) and may serve as an intermediate marker for colon cancer. In a characterization study, we have established the kinetics of AC growth and development over a period of 20 d following injection of rats with the carcinogen azoxymethane (AOM). AC are not present at 5 d post-injection, but are a constant feature at 10 d and thereafter. Multiple AC, presumably clonal, begin to evolve at 10 d and are consistent by 20 d, forming incipient microadenomata. We have examined 20 candidate chemopreventive agents for inhibition of AC. All agents were given in AIN-76 diet, at two dose levels, with injections of AOM. AC were measured after 5 weeks of growth. Among the most active AC-inhibiting agents were BHA, DFMO, quercetin, diallyl sulfide, 18 beta-glycyrrhetinic acid, and ascorbyl palmitate. In a post-initiation study, the differentiating agent sodium butyrate was ineffective, but piroxicam was highly effective in modulating AC growth. Further, piroxicam inhibited AC development at all stages of growth from single to polycryptal clusters of AC. The AC assay shows marked sensitivity and specificity for screening agents for chemoprevention of colon cancer.

Animals↗
PubMed1990

Triiodothyronine autoantibodies in Graves' disease: their changes after antithyroid therapy and relationship with the thyroglobulin antibodies.

UNLABELLED: Sera of 63 patients with Graves' disease, and 49 control subjects were assayed for T3 autoantibodies by a sensitive radioimmunoassay after being stripped of the endogenous thyroid hormone. T3 autoantibodies were demonstrated in 27% of patients with Graves' disease. After antithyroid treatment, T3 autoantibodies in 75% of the patients with positive antibody before therapy changed to negative titre during a follow-up period of 1 to 12 months. Also, a significant decrease of T3 autoantibodies was observed at 1 month after therapy in all patients who received antithyroid treatment. A further study of T3 autoantibodies and anti-thyroglobulin antibodies showed that the latter were demonstrated in 100% of patients with positive T3 autoantibodies and that T3 autoantibodies existed in about one third of patients with positive anti-thyroglobulin antibodies. The results suggested that T3 autoantibodies could be a subpopulation of the heterogenous anti-thyroglobulin antibodies. Although the fall of T3 autoantibodies in some patients was correlated to that of anti-thyroglobulin antibodies, the overall correlation between T3 autoantibodies and anti-thyroglobulin antibodies was poor. IN CONCLUSION: 1. T3 autoantibodies may be suppressed by antithyroid drugs. 2. Being a subpopulation of anti-thyroglobulin antibodies, T3 autoantibodies may be caused by an antigenic site within the big thyroglobulin molecule, whereas their titre was not correlated with that of the overall heterogenous anti-thyroglobulin antibodies.

Adolescent↗
PubMed1984

[Skin tests in asthmatic patients in Taiwan].

During the 22-year period from February, 1961 to December, 1982, 3550 asthmatic patients who visited the Taipei Municipal Chung-shing Hospital were skin tested with 35 allergens. The following results were obtained: The patients showed high skin reactivity to only inhaled allergens with positive rates in the order of 90.2% for house dust, 79.9% for candida, 73.0% for alternaria, 71.7% for aspergillus, 65.5% for cladosporium, 58.4% for tatami, 54.5% for penicillum and 52.3% for ragweed. While the sex had no influence on the incidence of skin test positivity, the positive rate peaked at around 20 to 30 years of age and decreased gradually thereafter. There was a significant correlation between PK titer and antigen threshold (r = +0.68). Although the healthy controls also showed positive skin reaction to house dust, none of them had an antigen threshold of higher than 16 (i.e. 16,000 X final dilution). Therefore an antigen threshold of 16 was suggested to be used as the cut point for the diagnosis of house dust allergen.

Adolescent↗
PubMedDate not supplied

Combination of direct swim-up technique and discontinuous Percoll gradient centrifugation for sperm preparation of oligoasthenozoospermic samples.

Sperm recovery for assisted reproduction in oligoasthenozoospermic patients is not satisfying either by the swim-up technique or by Percoll gradient centrifugation, and no single technique is constantly preferred. The design of this study was to evaluate the effects of combining the two methods on improving the efficacy of sperm preparation in these poor samples. For each semen sample, 1 mL was treated with a combination method, which used direct swim-up technique to recover motile sperm swimming to the supernatant, and then the residual semen was subjected to two-layer discontinuous Percoll gradient procedure for further recovery of motile sperm. Another 1 mL was prepared with two-layer discontinuous Percoll gradient centrifugation alone for comparison. Parameters measured included sperm concentration, number of progressively motile sperm, percentage of progressive motility, percentage of motile sperm recovery, amount of debris, percentage of normal forms according to Kruger's strict criteria, and motion characteristics of sperm using computer-aided motility analysis. The results of 30 oligoasthenozoospermic samples demonstrated that the combination method achieved a significantly greater recovery of motile sperm than the two-layer discontinuous Percoll gradient centrifugation did (43.2 +/- 19.7% vs. 32.2 +/- 14.3%, p < .05). The percentage of progressive motility was higher in the samples of the combination method than in those of Percoll gradient centrifugation alone, but the difference was not significant (63.7 +/- 21.8% vs. 58.7 +/- 20.1%). The debris of semen was removed equally well by both methods. The percentage of normal forms as well as motion characteristics, including curvilinear velocity, straight-line velocity, mean amplitude of lateral head displacement, and linearity, were similar in the samples treated by these two procedures. The combination of the direct swim-up technique and discontinuous Percoll gradient centrifugation combines the advantages of each procedure and results in greater recovery of motile sperm in oligoasthenozoospermic samples.

Cell Separation↗
PubMedDate not supplied

Effect of peritoneal fluid on sperm motility parameters in women with endometriosis.

To clarify the effect of peritoneal fluids (PF) of women with various stages of endometriosis on sperm motility, we utilized computer-aides sperm analysis (CASA) to analyze sperm movement characteristics. PF was collected in the early follicular phase (days 4-8) of the menstrual cycle from 48 women undergoing diagnostic laparoscopy. Only sperm samples having normal sperm parameters were chosen for study. Swim-up separation was performed for 1 h at 37 degrees C. Sperm suspension was mixed at a ratio of 1:1 with each of the following four groups: group 1, human tubal fluid (HTF) with 10% fetal bovine serum (control), group 2, normal PF (n = 16); group 3, minimal or mild endometriosis PF (n = 16); and group 4, moderate or severe endometriosis PF (n = 16). The mixtures were analyzed at 0, 1, 3, 6, and 24 h of co-incubation using the CASA system. At the end of the 24 h incubation, Supravital staining of sperm was done to check the viability of sperm in each group. Only time (F = 126.6, p < .001) has a significant effect on sperm motion parameters. At 6 h, sperm velocity (mean curvilinear velocity and mean straight line velocity) of the PF groups was significantly greater than that of the control, but there was no significant difference between each PF group. At 24 h, the PF groups maintained 50% of initial sperm viability, compared with 13% of initial viability in the control group (p < .001). There was no adverse effect of PF in patients with endometriosis on sperm motion parameters.

Ascitic Fluid↗
PubMedDate not supplied

Spermatozoa recovered by IxaPrep gradient have improved longevity and better motion characteristics than those by Percoll gradient.

To compare the effectiveness of various sperm preparation methods, we examined sperm concentration, percentage of progressive motility, recovery rate, and various motion characteristics in 32 semen samples after Percoll and IxaPrep preparations. Except for sperm concentration, which was much higher after IxaPrep preparation, no statistical differences existed between these two methods in terms of motile sperm concentration (MSC), recovery rate, mean curvilinear velocity (VCL), mean straight-line velocity (VSL) and mean amplitude of lateral head displacement (ALH). Among 22 samples that were allocated in a 37 degrees C, 5% CO2 incubator, the mean MSC after 3 hours was significantly higher following IxaPrep preparation than following Percoll preparation (63.2 x 10(6)/mL vs. 42.8 x 10(6)/mL, p < .03). VCL and VSL were much higher after IxaPrep preparation than after Percoll preparation, both at 3 hours (p < .01) and at 24 hours (p < .03). ALH was also higher after IxaPrep preparation than after Percoll preparation, and it was statistically significant after 3 hours of incubation (p < .03). We conclude that the IxaPrep gradient may be adopted as the preferred method to the Percoll gradient in preparing spermatozoa for assisted reproduction because of the spermatozoa's persistent and better motion activities after incubation.

Cell Separation↗
PubMedDate not supplied

Fibronectin levels in normal pregnancy and preeclampsia.

Vascular endothelial damage is reported to be the prime cause of preeclampsia, and elevated levels of fibronectin have been found before clinical signs of preeclampsia were manifested. The total plasma fibronectin concentrations in 212 blood samples from 173 normotensive healthy pregnant women at various gestational ages were measured. Fibronectin levels were also determined for 20 blood samples from 20 preeclamptic patients obtained at the time of clinical manifestation of preeclampsia. Blood samples from 46 non pregnant women of reproductive age were used as controls. The results showed that the total plasma fibronectin concentration during reproductive age was independent of age and the average level during pregnancy decreased with gestational age. Preeclamptic patients had a significantly elevated level of total fibronectin compared with healthy pregnant women. The total fibronectin concentration is a promising biochemical marker for preeclampsia, but a more specific endothelial method of measurement is needed before it is put to clinical use.

Adult↗