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Biomedical subjects

T M Ko

Publications and source records attributed to T M Ko.

At least 55 records · Page 3Linked to original sources
PubMed1993

Rapid detection of Chinese G gamma+(A gamma delta beta)zero-thalassemia by polymerase chain reaction.

The Chinese G gamma+(A gamma delta beta)zero-thalassemia is caused by a deletion of more than 80 kilobases. It has a beta(+)-thalassemia phenotype and should be differentiated from other mutations causing beta-thalassemia. Using polymerase chain reaction with three oligonucleotide primers bridging the breakpoints, the deletion can be detected easily. The method is useful in the genetic counseling and prenatal diagnosis of the at-risk families.

Alleles↗
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

Rapid detection of human hemoglobin Quong Sze by polymerase chain reaction.

Human hemoglobin Quong Size is a nondeletional defect involving codon 125 of the alpha 2-globin gene. The molecular defect is a T to C mutation, therefore, a new MspI site (CCGG) is created. Using a pair of flanking DNA primers and polymerase chain reaction, a DNA fragment of 339 basepairs (bp) was amplified. After MspI restriction and gel electrophoresis, the mutation could be clearly identified by the presence of two fragments, 108 and 123 bp. This method is rapid and simple and will be very useful in the genetic counseling of Southeast Asians, including the Chinese, in which nondeletional alpha-thalassemia defects are common.

Base Sequence↗
PubMed1993

Norplant-2 subdermal contraceptive system: experience in Taiwan.

Subdermal Norplant-2 implantation, developed for contraception based on sustained release of levonorgestrel, has already been conducted in many countries around the world. From October 1986 to November 1988, a total of 267 female volunteers were enrolled in Norplant studies at the National Taiwan University Hospital. After a follow-up of 36 months, only one of the 231 evaluable cases (0.4%) became pregnant. The continuation rate was 84.5%, 61.3%, and 52.0% at the end of 12, 24 and 36 months after insertion, respectively. Menstrual problems were the most common adverse effects and were also the main reason for discontinuation. In the 23 patients who wished to become pregnant, fertility occurred soon after removal of the Norplant implant. After insertion, serum total cholesterol and triglyceride levels significantly decreased and the hemoglobin concentrations were increased. No liver or renal toxicities were detected. The data suggest that Norplant-2 is a highly effective, safe and long-acting method of reversible contraception. It would be worthwhile to introduce this contraceptive system into Taiwan's family planning program.

Adult↗
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

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

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↗
PubMed1992

Rapid prenatal determination of fetal sex by polymerase chain reaction on amniocyte DNA.

Sex determination in early gestation is important for fetuses at risk for X-linked disorders or congenital adrenal hyperplasia. One hundred and seventy consecutive samples of amniocytes were collected between the 12th and 31st gestational week. Seven women received early amniocentesis before the 14th week. Fetal sex was determined by amplification of Y-specific DNA fragments within five hours. All results of the polymerase chain reaction, except for one false-negative, were compatible with cytogenetic analyses. Polymerase chain reaction of amniocyte DNA provides a rapid technique for sex determination in early gestation with high specificity and sensitivity.

Amniocentesis↗
PubMed1991

Molecular characterization of severe alpha-thalassemias causing hydrops fetalis in Taiwan.

alpha-Thalassemia hydrops fetalis is a common disorder in Taiwan. The condition causes perinatal death and many maternal obstetrical complications. In order to determine the molecular defects of this condition in Chinese, 87 unrelated families with this disorder were collected in the past 4 years. The molecular defects were studied by Southern blotting and DNA hybridization with phi zeta 1-globin gene and LO (a 0.4 kb BamHI/EcoRI fragment in the 5' flanking region of the zeta 2-globin gene) probes. Eighty-one (93.1%) fetuses had homozygous Southeast Asian deletion (- -SEA/- -SEA). Five (5.7%) fetuses were compound heterozygotes for the Southeast Asian deletion and Thailand deletion (- -SEA/- -THAI). The remaining fetus was a compound heterozygote for the Southeast Asian deletion and an uncharacterized nondeletional defect (- -SEA/(alpha alpha)Th). The molecular defects of alpha-thalassemia hydrops fetalis in Chinese are heterogeneous. This fact has important implications for genetic counseling and prenatal diagnosis.

Chromosome Deletion↗
PubMed1991

Restriction fragment length polymorphism analysis to study the genetic origin of complete hydatidiform mole.

To determine the genetic origin of the complete hydatidiform mole, 20 abnormal pregnancies were studied with restriction fragment length polymorphism with five genomic probes: EJ 6.6, beta-globin gene, 3'alpha-hypervariable region, J-Bir, and St14. In the 12 cases of molar pregnancy, pure paternal origin was proved in 11 cases, but both maternal and paternal inheritance were shown in only one case. In the cases with pure paternal origin, all of the restriction fragment length polymorphisms were homozygous, although those of the fathers were heterozygous at 15 loci. In the four cases that mimicked hydatidiform mole but were diagnosed as hydropic change of villi, both paternal and maternal inheritance were noted. In the four pregnancies with blighted ovum, both paternal and maternal inheritance were shown in three cases; and in one case with a balanced translocation between chromosomes 13 and 14, only paternal inheritance was noted. This study showed that most of the complete hydatidiform moles were caused by fertilization of an empty egg by a duplicated haploid sperm, but rare exceptions may exist.

Adult↗
PubMed1991

Acardius anceps: report of 3 cases.

Acardius anceps is an uncommon but serious consequence of multiple pregnancy, usually in monozygotic twins. There are great variations in gross appearance and pathologic features. Recently we have encountered 3 cases of acardius anceps in 3 sets of twin pregnancy. The subcutaneous edema was so extensive and severe that no facial structures could be recognized; however, the skull bones could be detected by prenatal ultrasound examination and confirmed by postnatal radiography. The hearts were all severely malformed and many of the visceral organs were also defective. Prenatal blood gas analysis in 2 affected fetuses showed severe hypoxemia. All 3 pregnancies were terminated before the normal co-twin reached viability. One set of the twins was delivered by hysterotomy because of the potential dystocia caused by bulky fetal mass due to severe hydropic change. Prenatal ultrasound examination is a very useful tool in the diagnosis and management of this anomaly.

Abnormalities, Multiple↗
PubMed1991

Selective reduction of multiple pregnancies in the first trimester or early second trimester.

Nine cases of multiple pregnancies, including 7 sets of triplets and 2 sets of quadruplets, were enrolled for selective fetal reduction between March 1989 and July 1990 at the National Taiwan University Hospital. Under transabdominal or transvaginal ultrasound guidance, potassium chloride was injected into the fetal cardiac chamber to kill the selected fetus during the 10-14th gestational week. The number of fetuses was reduced to two in all cases. No maternal complications occurred during the procedure. Six gravidas have given birth to 6 sets of healthy twins; two pregnancies are progressing smoothly at 26 and 23 weeks of gestation, respectively, and one case underwent spontaneous abortion 4 weeks after the procedure. Selective fetal reduction under ultrasound guidance is an acceptable method of preventing high perinatal mortality and morbidity of immature fetuses in grand multiple pregnancies.

Abortion, Induced↗
PubMed1991

Antenatal ultrasonic findings of craniofacial malformations.

Fetal craniofacial malformations were identified sonographically in 13 cases. Holoprosencephaly and median cleft syndrome were the most frequent findings. Cleft lip, cleft palate, single nostril, cyclopia and hypotelorism were also seen. Seven of the 13 cases (54%) had polyhydramnios. Amniocentesis was performed on 12 fetuses, and 5 of them showed autosomal trisomy. Accordingly, when craniofacial malformation is recognized antenatally, a careful survey of the fetus for other associated structural anomalies and cytogenetic study are indicated to aid in diagnosis and subsequent obstetric and neonatal management. Also screening for fetal craniofacial malformation is recommended during mid-trimester ultrasound examinations.

Abnormalities, Multiple↗
PubMed1991

Detection of beta-globin gene mutations by polymerase chain reaction.

The polymerase chain reaction and oligonucleotide probe hybridization technique were applied to the detection of two common mutations of the beta-globin gene found in Chinese, namely the 4-base pair deletion at the 41-42 codons and the C to T substitution at nucleotide 654 of IVS-2. The accuracy of the method was established using beta-thalassemia cases with known mutations or haplotypes of the restriction fragment length polymorphism (RFLP). A further 11 cases of thalassemia intermediate and thalassemia minor were then analysed with the same approach. Our results showed that 5 of the 11 cases carried the TCTT-deletion at codons 41-42. Our method is economical both in terms of materials and time needed and in an alternative to the use of the molecular RFLP approach in the prenatal diagnosis of beta-thalassemia.

Base Sequence↗
PubMed1991

Doppler velocimetry of intraplacental fetal arteries.

Doppler velocimetry of the umbilical and intraplacental fetal arteries was studied by color flow mapping in 39 normal pregnancies. The systolic-diastolic ratio (S/D) and pulsatility index of the intraplacental fetal artery downstream to the umbilical artery decreased significantly with advancing gestational age, and its S/Ds were persistently lower than those of the umbilical artery. The difference in the S/D between the umbilical artery and its intraplacental downstream branches decreased with advancing gestational age and approached zero as the pregnancy progressed to term. We conclude that intraplacental fetal arteries, possibly fetal arteries in main stem villi, can be imaged by color flow mapping and that there is a significant "resistance gradient" between the intraplacental fetal artery and the umbilical artery. Intraplacental fetal artery velocimetry using color flow mapping may give further insights into the umbilical-placental circulation.

Adult↗