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Biomedical subjects

T Y Lee

Publications and source records attributed to T Y Lee.

At least 19 recordsLinked to original sources
PubMed1992

In vivo CT measurement of blood-brain transfer constant of iopamidol in human brain tumors.

We have developed an in vivo method of measuring the blood-brain transfer constant (K) of iopamidol and the cerebral plasma volume (Vp) in brain tumors using a clinical X-ray CT scanner. In patient studies, Isovue 300 (iopamidol) was injected at a dosage of 1 ml/kg patient body weight. Serial CT scans of the tumor site and arterial blood samples from a radial artery were taken up to 48 min after injection. The leakage of iopamidol into the brain through the blood-brain barrier was modelled as an exchange process between two compartments, the intravascular plasma space and the tissue interstitial space. Using this model and the concentration measurements in blood plasma and tissue, quantitative estimates of K and Vp in brain tumors were obtained. In addition, distribution of the estimated values of K and Vp in tumors were displayed as false colour functional images overlaid on the conventional CT scan. In a study of twelve patients with anaplastic astrocytoma (n = 3), glioblastoma multiforme (n = 4) or metastases (n = 5) the mean K and Vp values in tumor were found to be 0.0273 +/- 0.0060 ml/min/g and 0.068 +/- 0.11 ml/g respectively. These values were significantly higher than those in grey or white matter in the contralateral 'normal' hemisphere (p less than 0.05). The functional images showed variations in K and Vp within the tumor which were difficult to perceive in the original contrast enhanced CT scans.

Astrocytoma↗
PubMed1992

Carrier detection and prenatal diagnosis of alpha-thalassemia of Southeast Asian deletion by polymerase chain reaction.

Alpha-thalassemia of Southeast Asian deletion (-- SEA/) is very common in Southeast Asia. Homozygosity of this genotype is the major cause of Hb Bart's hydrops fetalis in Taiwan. With polymerase chain reaction using three oligonucleotide primers bridging the common deletion breakpoint, a DNA fragment of 194 basepairs (bp) was amplified in chromosomes with the -- SEA determinant and a DNA fragment of 287 bp was amplified in chromosomes without this deletion. In our pilot study including 8 normal subjects, 20 obligate carriers, and 11 homozygotes of the deletion, all the genotypes were determined and then confirmed by Southern blotting and DNA hybridization with phi zeta globin gene probe. For prenatal diagnosis, 55 at-risk pregnancies were collected. Chorionic villus sampling was done in 51 cases and early amniocentesis was done in 4 cases. Fourteen cases (25.5%) were diagnosed as normal, 25 (45.5%) as heterozygotes, and 16 (29%) as homozygotes of -- SEA. All of the diagnoses were also confirmed as aforementioned. With polymerase chain reaction, the determination of the -- SEA deletion is straightforward and is much quicker and easier than with conventional Southern blotting and DNA hybridization. In areas with a high prevalence of -- SEA deletion, this method provides a rapid tool for carrier detection and prenatal diagnosis.

Asia, Southeastern↗
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

Regulatory effects of interleukin-4 on tumor-infiltrating lymphocytes derived from human renal cell carcinoma.

We have studied the effects of interleukin-4 (IL-4) on the expansion, proliferation, phenotype, and antitumor activity of tumor-infiltrating lymphocytes (TIL) derived from human renal cell carcinoma. Cultures were obtained from three primary renal tumors and one group of tumor-invaded, regional lymph nodes. IL-4 induced a significant increase in lymphocyte expansion and proliferation, but the response was dependent on the concurrent dose of IL-2 in culture. Increased growth activity was only observed in those cultures receiving low doses (20 U/ml) of IL-2 (average increase of fold expansion of 6.5, P < 0.01) with no changes in growth activity in the high dose (1000 U/ml) cultures. The combination of low dose IL-2 and IL-4 (200 U/ml) promoted lymphocyte growth significantly better than high dose IL-2 alone, the current standard growth regimen for in vitro expansion of TIL. TIL grown in the presence of IL-4 significantly reduced the level of non-specific, non-major histocompatibility complex-restricted antitumor activity (P < 0.01 for allogeneic renal, nonrenal, and NK-sensitive K562 cells), while exhibiting no effect on the level of autologous killing. This is in contrast to previous findings of significant enhancement of autologous antitumor activity using IL-4 on tumor-specific, melanoma-derived TIL. We also evaluated the effects of irradiated autologous tumor stimulation (TIL:tumor ratio, 10:1) on TIL cultures. Addition of autologous tumor cells increased expansion and proliferation of all cultures regardless of concurrent lymphokines present in the culture media (average increase fold expansion of 2.21, P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Carcinoma, Renal Cell↗
PubMed1992

The role of blocking factors and antipaternal lymphocytotoxic antibodies in the success of pregnancy in patients with recurrent spontaneous abortion.

OBJECTIVE: To elucidate the role of mixed lymphocyte reaction blocking factors (BF) and complement-dependent antipaternal lymphocytotoxic antibodies on the outcome of pregnancy in unexplained recurrent spontaneous aborters. DESIGN: A controlled study of immunotherapy in which the treated group was immunized with the husband's or a third party donor's lymphocytes and the control group received autologous lymphocytes. SETTING: Tertiary care institution. PATIENTS: Forty-three patients in the control group and 48 patients in the treated group. INTERVENTION: The before and after immunization levels of BF and antipaternal lymphocytotoxic antibodies were measured. MAIN OUTCOME MEASURES: The existence or changing pattern of BF and antipaternal lymphocytotoxic antibodies levels before and after immunization had no influence on the pregnancy outcome in either group of patients. CONCLUSION: Neither BF nor antipaternal lymphocytotoxic antibodies is essential for successful pregnancy. They probably reflect the immunological response of the mother to exposure to fetal antigens.

Abortion, Habitual↗
PubMed1992

An absorptiometry method for the determination of arterial blood concentration of injected iodinated contrast agent.

A single photon absorptiometry method to measure the arterial concentration of injected iodinated contrast agent was developed. A prototype absorptiometry unit was built which consists of either a square or circular cross section acrylic (polymethylmethacrylate) cuvette connected to an arterial catheter at one end and a paristaltic pump at the other via PE60 surgical tubing. At opposing ends of the length of the cuvette were a 0.4 GBq 125I source and a scintillation crystal/photomultiplier tube assembly. This assembly was connected to a single-channel analyser (SCA)/scaler unit to count the transmitted photons through the cuvette. The scaler was interfaced to an IBM PC and counts accumulated in preset time intervals were transmitted to the computer via a serial interface. Experiments were performed to calibrate the unit for measurement of blood concentration of contrast agent (Isovue 300) and to determine the dispersion characteristics of the unit. Deconvolution was used to correct the measured concentration waveform for the dispersion introduced by passage through the lead-in tubing and the cuvette. The precision of concentration measurements was determined to be between 5 and 10% using computer simulations and theoretical calculations. The method was used successfully in a number of patient and animal studies to measure the contrast concentration in blood following intravenous injection of contrast agent.

Absorptiometry, Photon↗
PubMed1992

Topical ofloxacin in the treatment of Pseudomonas keratitis in a rabbit model.

Ofloxacin, a new quinolone antibiotic with a broad spectrum of activity, is very effective against Pseudomonas aeruginosa in vitro. Its effectiveness was studied in a rabbit model of tobramycin-sensitive P. aeruginosa. Treatment groups received either vehicle, tobramycin 0.3%, or ofloxacin 0.3%. Twelve hours of treatment decreased the bacterial counts from a mean of 2.2 +/- 0.7 x 10(6) colony forming units (cfu) per cornea in the vehicle group to means of 513 +/- 670 and 435 +/- 524 cfu in the tobramycin and ofloxacin groups, respectively. This decrease in bacterial counts was statistically significant (p = 0.001 for tobramycin and ofloxacin each compared with control, p = 0.86 for tobramycin compared with ofloxacin). After seven days, all antibiotic-treated corneas were sterile and the epithelial defects healed at comparable rates. Aqueous humor drug levels were higher in infected eyes without an intact epithelium (p = 0.02); in eyes with intact epithelium, concentrations of ofloxacin were higher than were those of tobramycin (p = 0.002). In this animal model, ofloxacin proved to be an effective antibiotic with no evidence of toxicity.

Administration, Topical↗
PubMed1992

Detection of Mycobacterium tuberculosis in clinical samples from patients with tuberculosis or other pulmonary diseases by polymerase chain reaction.

Polymerase chain reaction (PCR) using primers targeting the IS6110 repetitive sequence was employed to detect Mycobacterium tuberculosis in 228 samples from patients with tuberculosis or other pulmonary diseases and controls, and the results were compared with culture and clinical findings. None of culture negative samples from 17 healthy controls were PCR positive. Of 109 active tuberculosis patients under chemotherapy, 88 (80.7%) were PCR positive and were significantly higher than 63 (57.8%) positive by culture. Fifty-nine (93.7) of 63 culture positive and 29 (63.0%) of 46 culture negative specimens contained M. tuberculosis detectable by PCR. In 41 specimens from inactive tuberculosis patients who visited to the chest clinic because of chest problems, 16 (39.0%) also gave PCR positive results. In addition, 14 (46.7%) of 30 specimens submitted for M. tuberculosis culture from patients with pulmonary diseases were PCR positive. Presumptive diagnosis of these PCR positive patients was bronchitis, pneumonia, bronchial asthma, etc. Therefore, this study suggests that PCR is sensitive and specific in detecting M. tuberculosis in clinical specimens. However, the interpretation of the PCR results in specimens from patients with pulmonary diseases should be done cautiously in areas with a high prevalence of tuberculosis.

Base Sequence↗
PubMed1992

Suspected anaphylactoid shock to aminocaproic acid (plaslloid) during operation.

Epsilon-aminocaproic acid (plaslloid) is one of the most common hemostatics used perioperatively. Although some minor untoward effects in association with its use are not uncommon, the incidence of anaphylactoid shock is extremely rare, especially in a patient under general anesthesia. Recently we came across a severe anaphylactoid reaction, possibly as a result of administration of plaslloid in a patient who was undergoing elective surgery for cervical carcinoma. It was manifested by profound hypotension, tachycardia, hypoxemia, skin-wheel eruption and conjunctival and labial edema. She was successfully resuscitated with prompt volume expansion and epinephrine injection. Our experience in the management of this patient is, hereunder, reported and discussed.

Aminocaproic Acid↗
PubMed1992

Prenatal cytogenetic diagnosis in amniocentesis.

From 1982 to 1990, cytogenetic studies were successfully conducted in 2,975 (96.19%) of the 3,096 pregnant women who underwent amniocentesis. The average maternal age was 33.7 years and the average gestational age was 18.1 weeks. Common indications of amniocentesis included advanced maternal age (AMA) (54.76%), previous fetus with chromosomal aberrations (6.82%) or gross anomalies (5.01%), intrauterine gross anomaly (4.97%) and maternal exposure to drugs or radiation (5.28%). Among the 89 cases (2.99%) with detected chromosomal aberrations, 53 were numeric (31 trisomies, 21 sex chromosome aberrations and one tripoidy) and 36 were structural (six de novo and 30 hereditary structural rearrangement). The incidence of chromosomal aberrations was 2.03% in cases with AMA. While only four of the 143 cases with previous fetal trisomy 21 had recurrence, the recurrent rate was 90.91% in 11 cases with previous fetal chromosomal translocation. Thirty (20.27%) of the 148 cases with abnormal sonograms showed chromosomal aberrations. Certain congenital anomalies are closely associated with cytogenetic changes: duodenal atresia and trisomy 21; cystic hygroma and 45,X; and polyhydramnios and trisomy 18. Only two of the 157 cases with indications of drug or radiation exposure had abnormal cytogenetic studies. Two of the 53 cases with detected numerical aberrations (47,XXY and 47,XXX) and 27 cases with hereditary structural rearrangement elected to continue their pregnancies. All of these babies were delivered without gross anomalies. This study suggests that for prenatal diagnosis. However, complementary measures, such as routine antenatal ultrasound and maternal serum alphafetoprotein, should be added to increase the efficacy of genetic amniocentesis.

Adolescent↗
PubMed1992

Pericentric inversions of chromosome 9 in Taiwanese fetuses.

Using trypsin-Giemsa banding, a total of 1,350 unrelated Chinese fetuses were studied for pericentric inversion of chromosome 9 [inv(9) (p11; q13)]. Sixteen cases (1.2%) were found to have this variant. The prevalence was higher than that in a previous report on Asians. All the fetuses with inv(9) were born with a normal phenotype.

Chromosome Inversion↗
PubMed1992

Treatment and outcome of unexplained recurrent spontaneous abortions in subclinical autoimmune disorders.

Patients with a history of three or more fetal losses before a gestational age of 20 weeks were examined. Only patients with normal chromosomal, hormonal and anatomic findings were included in this study. These patients were tested for the antinuclear antibody, the C3 and C4 levels, anti-ENA [Ro(SSA), La(SSB), SM, RNP, scl-70], anti-single-stranded DNA and anti-double-stranded DNA, lupus anticoagulant, anticardiolipin and antiphosphotidylserine. All of these patients were free of any symptoms, except for the repeated abortions. The results showed that 10 out of 213 (4.7%) patients with unexplained recurrent spontaneous abortions had abnormal serologic tests, and 28% of the abortions (nine out of 32 abortions) occurred during the second trimester. With treatment of low-dose aspirin alone, or in combination with prednisolone, two out of 11 pregnancies in these 10 patients resulted in repeated abortions (18%), which was significantly lower than their previous abortion rate where 32 out of 33 pregnancies resulted in abortions (97%). Four babies (three term and one premature) were delivered without any abnormalities and the other five pregnancies are beyond the 28th week of gestation and are progressing smoothly. This study revealed that subclinical autoimmune disorders may play a role in recurrent spontaneous abortions and adequate treatment can improve the pregnancy outcome.

Abortion, Habitual↗
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↗
PubMed1992

Combined cornual pregnancy and intrauterine twin pregnancy after in vitro fertilization and embryo transfer: report of a case.

A case of combined cornual pregnancy and intrauterine twin pregnancy after in vitro fertilization (IVF) and transfer of six embryos is presented. The case was diagnosed as intrauterine triplets ultrasonographically at seven weeks of gestation. Unfortunately, the patient suffered from severe lower abdominal pain and hypovolemic shock at 10 weeks of gestation, and an emergent laparotomy was done. During the operation, a ruptured cornual pregnancy with accompanying hemoperitoneum was found. Because fetal heart beats were not detected by intraoperative ultrasonography in the other two intrauterine fetuses, evacuation of the gestational contents through the uterine defect was done, and the rupture site was repaired. The incidence, mechanism and management of heterotopic pregnancies after in vitro fertilization and embryo transfer are discussed.

Adult↗
PubMed1992

Dystrophin gene deletion in Chinese Duchenne/Becker muscular dystrophy patients via multiplex DNA amplification.

Duchenne/Becker muscular dystrophy (DMD/BMD) is a progressive muscle-wasting disease. The dystrophin gene responsible for the disease is the largest human gene ever cloned and is prone to gross gene deletion in two "hot spot" regions. Using nine pairs of oligonucleotide primers deduced from the two regions, we have screened 23 unrelated Chinese DMD/BMD patients by multiplex polymerase chain reaction. Nine (39%) patients were noted to have gene deletion, one in the 5' terminus and eight in the distal half of the gene. The incidence is similar to that reported in other large series mainly on Caucasian patients. The "hot-spot" regions also seem to be present in Chinese patients. Multiplex gene amplification for deletion analysis is useful in the diagnosis of patients with neuromuscular diseases and is an important aid in the prenatal diagnosis and genetic counseling of at-risk families.

Base Sequence↗