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Biomedical subjects

T H Bui

Publications and source records attributed to T H Bui.

54 records · Page 3Linked to original sources
PubMed1992

Prenatal investigation of a 45,X/46,X,r(?) karyotype in amniocytes using fluorescence in situ hybridization with an X-centromeric probe.

The karyotype of cultured amniotic fluid cells obtained on the indication of advanced maternal age was shown to be a mosaic 45,X/46,X,r(?). The small size and banding pattern made it difficult to determine whether the ring was derived from and X or a Y chromosome, or even from an autosome. By using an X-centromeric probe and fluorescence in situ hybridization (FISH), we demonstrated the ring to have an X centromere. Thus, a more complete genetic counselling was possible. This confirms the usefulness of FISH in identifying and characterizing this and other chromosome rearrangements in prenatal diagnosis.

Adult↗
PubMed1992

Prenatal diagnosis of distal arthrogryposis type I by ultrasonography.

Two consecutive pregnancies in a woman with initially undiagnosed type I distal arthrogryposis (DA) are reported. A prenatal diagnosis of the condition was made by ultrasound in the 17th week of gestation in one of the pregnancies, whereas in the subsequent pregnancy the disorder was excluded as early as 13 weeks' gestation. The diagnoses were verified at birth. The feasibility of prenatal diagnosis of DA type I in the second trimester is thus confirmed and its possibility in the late first trimester is suggested.

Adult↗
PubMed1991

Color Doppler studies in trophoblastic tumors: a preliminary report.

Ten women, referred because of a strong suspicion of gestational trophoblastic neoplasia, were examined by abdominal real-time ultrasound and color Doppler. The results were compared to those of pelvic angiography. In all but one case color Doppler examination revealed areas of increased vascularity. In all cases the findings of color Doppler and pelvic angiography agreed. Real-time ultrasound failed to detect abnormal uterine echoes in three of the patients where the other methods indicated tumor. The present study indicates that color Doppler could be of great value in a non-invasive assessment of trophoblastic tumors.

Journal Article↗
PubMed1984

European collaborative study on prenatal diagnosis: mosaicism, pseudomosaicism and single abnormal cells in amniotic fluid cell cultures.

A report is given of the results of a European collaborative study on mosaicism, pseudomosaicism and single abnormal cells in amniotic fluid cell cultures. The mean frequency of cases with mosaicism was 0.10 per cent, with pseudomosaicism 0.64 per cent and with single abnormal cells 2.83 per cent in a series of 44 170 amniotic fluid samples. There was no significant difference between the colony (in situ) and the flask method with regard to the frequency of mosaicism. Pseudomosaicism and single abnormal cells were more frequent in cases studied with the flask method probably due to other factors than the method of cultivation of the cells. The frequency of maternal cell contamination was 0.17 per cent and the frequency of wrong sex assignment was 0.11 per cent. A more correct estimation is obtained if these frequencies are doubled. There was a considerable variation between laboratories with regard to the frequencies given above. One reason for this variation is that there are no sharp limits between mosaicism, pseudomosaicism and single abnormal cells. Thus the material contained cases diagnosed as having pseudomosaicism which turned out to be mosaics at birth and to have an abnormal phenotype. These cases were very rare but pose a definite problem in prenatal cytogenetic diagnosis.

Amniotic Fluid↗
PubMed1983

The 11q;22q translocation: a collaborative study of 20 new cases and analysis of 110 families.

Following a previous collaborative study (Fraccaro et al. 1980), 20 new cases of 11q;22q translocation are described. Twelve families were ascertained through an unbalanced carrier of the translocation and eight cases were ascertained as balanced carriers. A segregation analysis was performed on the 110 families so far published. It was concluded that the 11q;22q translocation is a relatively frequent event, and that all the cases thus far reported might have the same breakpoints at 11q23.3 and 22q11.2. The translocation seems to be independent of environmental factors and it seems to have a low rate of mutation as indicated by the scarcity of de novo cases. The new data confirmed that only one type of unbalanced karyotype (47,XX or XY+der(22)t(11;22)(q23.3;q11.2)) is found among the offspring of the translocation carriers. The minimal overall recurrence risk for an unbalanced translocation was estimated to 2%. There was no difference between the recurrence risks for male and female balanced carriers, while the trend was confirmed of an excess of female balanced carriers among the phenotypically normal offspring of the t(11;22) female carriers.

Abnormalities, Multiple↗
PubMed1983

Dyggve-Melchior-Clausen dysplasia. Morphological and biochemical findings in cartilage growth zones.

The results of light and electron microscopic examination and of biochemical proteoglycan studies of costochondral and iliac crest biopsies from a recently diagnosed case of Dyggve-Melchior-Clausen dysplasia are reported. At light microscopy of resting cartilage large lacunae containing clusters of five or more chondrocytes were seen in some areas. In the hyaline cartilage there were scattered fibrous foci but no mineralized areas. Electron microscopy revealed chondrocytes containing widened cisternae of rough endoplasmic reticulum and vesicles coated with a smooth single-layered membrane. The content of the cisternae and of the vesicles was amorphous. Throughout the cartilage a considerable proportion of the chondrocytes displayed more or less pronounced necrobiotic changes. The biochemical analysis showed an increased amount of glucosaminoglycans in the cartilage and indicated that the ability of proteoglycan monomers to reaggregate to hyaluronic acid chains was decreased. Our findings support the suggestion that Dyggve-Melchior-Clausen dysplasia is due to a disturbance in proteoglycan metabolism.

Cartilage↗
PubMed1982

A familial pericentric inversion of chromosome 8 analysed with a high resolution chromosome banding technique.

A familial pericentric inversion of chromosome 8 is described. The break points were localized by a high resolution chromosome banding technique and found to be inv(8)(p23.108q12.100). None of the family members had an unbalanced product of the inversion. There were no phenotypical abnormalities in the carriers. The break points and segregation pattern are compared with those of previously reported pericentric inversion of chromosome 8.

Adult↗
PubMed1981

A girl with an interstitial deletion of the short arm of chromosome 3 studied with a high-resolution banding technique.

A girl with delayed growth in body height and weight, retarded psychomotor development, facial dysmorphism, high-arched palate, extension defects of elbows, and a probable hearing impairment is presented. A chromosome investigation by both conventional and high-resolution banding techniques revealed an apparently pure interstitial deletion of the proximal segment of the short arm of chromosome 3 (46,XX,del(3) (p11p14.2) de novo). The paternal karyotype is 47,XYY. The clinical features of the patient are compared with those of two previously reported cases in the literature with an interstitial 3p deletion.

Abnormalities, Multiple↗
PubMed1980

Ring chromosome 14 in a mentally retarded girl.

A case of ring chromosome 14 in a 12-year-old girl, showing mental retardation, epilepsy and minor somatic abnormalities, is described and compared with five previously reported cases with the same chromosome aberration.

Abnormalities, Multiple↗
PubMed1976

DNA repair and frequency of x-ray and u.v.-light induced chromosome aberrations in leukocytes from patients with Down's syndrome.

DNA-repair and the frequency of chromosome aberration after u.v. and X-ray irradiation was studied on leukocytes from patients with Down's syndrome. The u.v.-induced DNA-repair synthesis was followed by the incorporation of [3H]thymidine in the presence of hydroxyurea. Similar dose-response curves were established for Down's syndrome leukocytes and controls. The cells from patients with Down's syndrome incorporated 70-75% of the activity of control cells at the various doses (32-196 erg/mm.2). This difference was significant for the two highest u.v.-doses (P less than 0-01). The yield of dicentric chromosomes after X-ray exposure (150 rad.) was 35% higher in Down's syndrome leukocytes than in the control cells (P less than 0-001). Combined u.v. and X-ray irradiation caused a twofold increase in the frequency of dicentric chromosomes in control cells, while the increase was only 27% in Down's syndrome leukocytes. This synergistic effect of u.v. and X-ray irradiation on the yield of dicentric chromosomes suggests that healing of X-ray and u.v.-induced DNA lesions may partly utilize the same repair enzymes. The results also indicate that DNA repair mechanisms are impaired in leukocytes from patients with Down's syndrome, which may contribute to the increased incidence of leukemia and the susceptibility to X-ray irradiation in this disorder.

Adult↗
PubMedDate not supplied

Prenatal diagnosis of chondroectodermal dysplasia with fetoscopy.

Chondroectodermal dysplasia (Ellis-van Creveld syndrome) has previously been diagnosed prenatally only once, using fetoscopy. We report on two consecutive pregnancies in a woman at risk of having a child with the syndrome during which fetoscopic visualization was performed. Ellis-van Creveld syndrome was diagnosed prenatally in one instance, while it could be excluded in the other one. Non-invasive prenatal diagnosis of the syndrome is discussed.

Adult↗
PubMedDate not supplied

Amniotic septostomy for the treatment of twin oligohydramnios-polyhydramnios sequence.

OBJECTIVE: To report our experience with intentional puncture of the intervening membrane ('septostomy') for the treatment of the twin oligohydramnios-polyhydramnios sequence (TOPS). METHODS: 12 patients were diagnosed with TOPS based on ultrasonographic findings. A 20- to 22-gauge spinal needle was used to puncture the membrane between the twins without any attempt at amnioreduction in 9 patients, while the procedure was combined with amnioreductions in 3 patients. RESULTS: Gestational age was 23.1 +/- 3.3 weeks at the time of septostomy and 31.1 +/- 4.4 weeks at delivery. Rapid accumulation of fluid around the 'stuck' fetus occurred in all cases following a single procedure. Three of the 24 fetuses died in utero and 1 died on the fifth day of life, for a combined survival of 83.3%. In the survivors, the septostomy to delivery interval ranged between 0.6 and 13 weeks (mean +/- SD 8.3 +/- 4.8). CONCLUSION: Amniotic septostomy is a promising new method for the management of TOPS and is associated with survival rates that are better than, or comparable to, more invasive modalities. A multicenter trial comparing septostomy to other modalities is warranted.

Amnion↗
PubMedDate not supplied

Screening of fetal stem cells for infection and cytogenetic abnormalities.

Fetal stem cell transplantation may rely on material from therapeutic abortions. It is essential that the stem cell transplant does not transmit any microorganisms that may affect the fetus and that genetically abnormal cells are avoided. To evaluate such contamination, human fetal stem cells collected February 1992 - December 1993 were analyzed for bacterial and fungal growth, and the placentas were karyotyped. Four samples of 70 were positive for different pathogens. Serological screening of 43 women during this period resulted in five seroconversions and revealed one carrier of anti-HCV. Karyotyping revealed two abnormal findings out of 72 samples. Thus, the concept of using material from therapeutic abortions is safe.

Abortion, Induced↗