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The-Hung Bui

Publications and source records attributed to The-Hung Bui.

10 recordsLinked to original sources
PubMed2006

Depression and suicidal ideation after predictive testing for Huntington's disease: a two-year follow-up study.

The present study reports a two-year follow-up of psychological effects of predictive testing for Huntington's disease. Questionnaires assessing depression, general health, well-being, self injurious behavior, life satisfaction, and lifestyle were completed by 35 carriers and 58 non-carriers before the predictive test, and 2, 6, 12, and 24 months afterwards. Both carriers and non-carriers showed high suicidal ideation before the predictive testing. Depression scores and frequency of suicidal thoughts increased for carriers, compared to non-carriers, over time. There were no differences regarding life satisfaction or life style between carriers and non-carriers. Predictive testing was beneficial in reducing overall ill-health symptoms and increasing well-being for those initially expressing concern about Huntington's disease. The importance of assessing suicidal ideation and of continuing to provide adequate support is emphasized.

Depression↗
PubMed2002

[New analytic methods provide answers regarding chromosome aberrations in 1-2 days].

During the last decade, new tools have been made available to clinical genetics laboratories through the technologies developed for gene scanning, sequencing, detection of short tandem repeats (STRs) and single nucleotide polymorphisms (SNPs). Two methods (interphase fluorescence in situ hybridization, FISH, and quantitative fluorescence PCR, QF-PCR assay) have been introduced recently for the rapid prenatal diagnosis of numerical chromosome abnormalities within 1-2 days after sample collections, thus obviating the 7-14 days delay needed for cell culture associated with conventional chromosome analysis. Most commonly, probes or STRs specific for chromosomes 13, 18, 21, X and Y are used as, depending on the indications for invasive tests, numerical abnormalities involving these chromosomes account for the vast majority of the chromosome aberrations identified prenatally. The advantage of QF-PCR over inter-phase FISH is that the former is considered substantially more cost-effective, in particular when larger sample numbers are processed.

Chromosome Aberrations↗
PubMed2002

Pre-implantation genetic diagnosis.

Pre-implantation genetic diagnosis is an alternative to prenatal diagnosis for a select group of patients. Patients have to go through in vitro fertilization in order to produce embryos in vitro, from which one or two cells are removed at the 8-cell stage. A fluorescence in situ hybridization or polymerase chain reaction is carried out for the genetic diagnosis. Fluorescence in situ hybridization is used for the analysis of chromosomes for sexing for X-linked disease, chromosome abnormalities and aneuploidy screening. Aneuploidy screening is performed for infertile patients going through in vitro fertilization to try to improve their pregnancy rate. A polymerase chain reaction is used for the diagnosis of single-gene disorders. Since the risk of contamination and allele dropout is high with a polymerase chain reaction, linked or unlinked markers are usually used in a fluorescent multiplex polymerase chain reaction. New techniques, for example comparative genomic hybridization, allow the analysis of all of the chromosomes from one cell at one time. The ethical implications of pre-implantation genetic diagnosis are immense as the technique has already been used for social sexing and human leukocyte antigen matching.

Chromosome Aberrations↗
PubMed2002

Mitochondrial diseases.

Mitochondrial disorders are caused by deficient respiratory chain function, resulting in a complex series of pathophysiological events. Genetic counselling is complicated because the respiratory chain subunits are encoded by both nuclear and mitochondrial DNA genes. Only a minority of the nuclear genes involved in mitochondrial function have been identified, and even fewer are associated with human mitochondrial disease. Mutations in mitochondrial DNA are particularly challenging because of the complexities of mitochondrial genetics: the mitochondrial DNA is strictly maternally inherited; there are 10(3)-10(4) copies of mitochondrial DNA in somatic cells; affected individuals often have a mixture of normal and mutated mitochondrial DNA (mitochondrial DNA heteroplasmy), the level of mutated mitochondrial DNA (the mitochondrial DNA mutation load) may vary widely between different maternally related individuals, between tissues and with time; a particular minimal threshold of mutated mitochondrial DNA is required to impair respiratory chain function; and there is not always a good correlation between mutant load and phenotype.

DNA, Mitochondrial↗
PubMed2002

Prenatal diagnosis: molecular genetics and cytogenetics.

The technologies developed for the Human Genome Project, the recent surge of available DNA sequences resulting from it and the increasing pace of gene discoveries and characterization have all contributed to new technical platforms that have enhanced the spectrum of disorders that can be diagnosed prenatally. The importance of determining the disease-causing mutation or the informativeness of linked genetic markers before embarking upon a DNA-based prenatal diagnosis is, however, still emphasized. Different fluorescence in situ hybridization (FISH) technologies provide increased resolution for the elucidation of structural chromosome abnormalities that cannot be resolved by more conventional cytogenetic analyses, including microdeletion syndromes, cryptic or subtle duplications and translocations, complex rearrangements involving many chromosomes, and marker chromosomes. Interphase FISH and the quantitative fluorescence polymerase chain reaction are efficient tools for the rapid prenatal diagnosis of selected aneuploidies, the latter being considered to be most cost-effective if analyses are performed on a large scale. There is some debate surrounding whether this approach should be employed as an adjunct to karyotyping or whether it should be used as a stand-alone test in selected groups of women.

Chromosome Disorders↗
PubMed2002

Prenatal T-cell reconstitution after in utero transplantation with fetal liver cells in a patient with X-linked severe combined immunodeficiency.

OBJECTIVE: Fetuses with severe combined immunodeficiency may be treated with intrauterine transplantation of fetal hematopoietic stem cells. In previous reports on intrauterine transplantation with T-cell-depleted bone marrow, repeated injections have led to partial immunoreconstitution at birth, with subnormal T-cell counts and a delayed response to mitogens. STUDY DESIGN: A male fetus with X-linked severe combined immunodeficiency because of a stop mutation in the gene encoding the common gamma chain of cytokine receptors was transplanted in week 14 of gestation with a single injection of 7 x 10(7) cryopreserved nucleated fetal liver cells (9 x 10(8) cells per estimated kilogram fetal weight) into the fetal abdomen. At 24 and 33 weeks of gestational age, fetal blood samples were taken to detect evidence of engraftment. Fetal mixed chimerism was determined using polymerase chain reaction amplification of a variable number of tandem repeats and was verified by genomic HLA class II typing and flow cytometry. RESULTS: The course of pregnancy, delivery, and the first 18 months of life have been uncomplicated. At week 24 of gestation, donor HLA class II alleles were detected at a low level in the background of the recipient's fetal HLA genotype. The chimeric proportion of donor cells was about 10% at 24 weeks of gestation, increasing to 50% at 33 weeks of gestation. Whereas the T-cell fraction was still markedly reduced in week 24, it increased thereafter and was in the normal range from week 33 of gestation. In vitro response to T-cell mitogens was normal from birth. CONCLUSION: In utero transplantation of cryopreserved fetal liver cells in week 14 of gestation with a single injection led to complete T- and NK-cell reconstitution at birth. Signs of engraftment were found already in week 24 of gestation. We consider intrauterine transplantation a valuable experimental method and a useful adjunct to postnatal transplantation and gene therapy in the treatment of severe combined immunodeficiency.

Female↗
PubMedDate not supplied

The introduction of QF-PCR in prenatal diagnosis of fetal aneuploidies: time for reconsideration.

Quantitative fluorescent polymerase chain reaction (QF-PCR) has recently entered the field of prenatal diagnosis to overcome the need to culture fetal cells, hence to allow rapid diagnosis of some selected chromosomal anomalies. We reviewed the studies on the accuracy of QF-PCR in detecting chromosomal anomalies at prenatal diagnosis. Overall, 22 504 samples have been analysed. The detection rate of aneuploidies of the selected chromosomes (13, 18 and 21, and X and Y) was 98.6% (95% confidence interval 97.8-99.3). QF-PCR might play a major role and be considered a valid alternative to the full karyotype. Being less expensive, and almost entirely automated, more women could undergo invasive prenatal diagnosis without significant increase in health expenditure. By using QF-PCR as a stand-alone test, the chances of non diagnosing the commonest, and the only chromosome anomalies which do increase in frequency with maternal age, are approximately one in 150 abnormal karyotypes, or one in 10-30 000 samples, based on the age distribution. These error rates might be deemed acceptable, although most structural chromosomal anomalies will be missed. At present, women are rarely informed about the full spectrum of the conditions which might be diagnosed via amniocentesis or chorionic villous sampling. Some of these anomalies might be acceptable, in view of their limited or uncertain clinical relevance, and decision analysis might, in the majority of cases, confine the full karyotype to selected women who have specific indications.

Aneuploidy↗