Genetic influences of prolonged gestation: maternal, paternal, or fetal?
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Female↗
Biomedical subjects
Sun-Wei Guo
Publications and source records attributed to Sun-Wei Guo.
Genomic alterations in the endometrium may be a proximate cause for endometriosis.
OBJECTIVE: To test the hypothesis that endometriosis may originate from genomic alterations in the endometrium by genomic analysis of endometrial tissues in patients with endometriosis and compare them with those from normal controls. METHODS: Endometrial tissue samples were taken from five women with endometriosis. For controls, we used endometrial tissue samples from four women who underwent elective abortions and one sample from placenta. Using array-based comparative genomic hybridization (CGH), we determined the normal range of variation in CGH signals using normal controls. CGH results were further confirmed by real-time quantitative PCR and loss of heterozygosity analysis. RESULTS: We identified several regions of genomic alterations in all five patients. Some of these regions were the same regions identified previously in endometriotic lesions. For select markers, the genomic alterations were confirmed by real-time PCR and LOH analyses. CONCLUSIONS: There is evidence that the endometrium in women with endometriosis has genomic alterations. This is consistent with numerous reports that the endometrium of women with endometriosis differ from those of women without. Our finding suggests that genomic alterations in the endometrium may be a proximate cause for endometriosis.
Adult↗
The link between exposure to dioxin and endometriosis: a critical reappraisal of primate data.
Endometriosis is a common and enigmatic disease affecting women of reproductive age. In 1993, Dr. Sherry Rier and her colleagues reported a serendipitous finding that quickly sent a shock wave through the endometriosis research community. They found that rhesus monkeys exposed daily for 4 years to dioxin developed endometriosis, with incidence and severity related to dose. The study prompted more animal and epidemiologic studies regarding the link between dioxin exposure and endometriosis. Yet, 10 years after the first piece of evidence was reported, the primate data are still equivocal, and the human data supporting the dioxin-endometriosis association are scanty and conflicting. While many reviewers of the subject recognize the need for more data, other reviewers tend to discount negative studies when reviewing positive studies. In this paper, a critical reappraisal of all evidence from human and primate data is presented. While there is evidence suggesting that exposure to dioxin may facilitate the short-term survival of endometrial implants in non-human primates, this evidence is not supported by both human and non-human primate studies evaluating the relationship between dioxin exposure and the development of spontaneous endometriosis. Weighing all converging evidence, it seems that there are no solid, credible data available at this moment to support the hypothesis that dioxin exposure may lead to the development of endometriosis.
Animals↗
Statistical methods for detecting genomic alterations through array-based comparative genomic hybridization (CGH).
Array-based comparative genomic hybridization (ABCGH) is an emerging high-resolution and high-throughput molecular genetic technique that allows genome-wide screening for chromosome alterations associated with tumorigenesis. Like the cDNA microarrays, ABCGH uses two differentially labeled test and reference DNAs which are cohybridized to cloned genomic fragments immobilized on glass slides. The hybridized DNAs are then detected in two different fluorochromes, and the significant deviation from unity in the ratios of the digitized intensity values is indicative of copy-number differences between the test and reference genomes. Proper statistical analyses need to account for many sources of variation besides genuine differences between the two genomes. In particular, spatial correlations, the variable nature of the ratio variance and non-Normal distribution call for careful statistical modeling. We propose two new statistics, the standard t-statistic and its modification with variances smoothed along the genome, and two tests for each statistic, the standard t-test and a test based on the hybrid adaptive spline (HAS). Simulations indicate that the smoothed t-statistic always improves the performance over the standard t-statistic. The t-tests are more powerful in detecting isolated alterations while those based on HAS are more powerful in detecting a cluster of alterations. We apply the proposed methods to the identification of genomic alterations in endometrium in women with endometriosis.
Chromosome Aberrations↗
Three color cDNA microarrays: quantitative assessment through the use of fluorescein-labeled probes.
Gene expression studies using microarrays have great potential to generate new insights into human disease pathogenesis, but data quality remains a major obstacle. In particular, there does not exist a method to determine prior to hybridization whether an array will yield high quality data, given good study design and target preparation. We have solved this problem through development of a three-color cDNA microarray platform where printed probes are fluorescein labeled, but are spectrally compatible with Cy3 and Cy5 dye-labeled targets when using confocal laser scanners possessing narrow bandwidths. This approach enables prehybridization evaluation of array/spot morphology, DNA deposition and retention and background levels. By using these measurements and the intra-slide coefficient of variation for fluorescence intensity we show that slides in the same batch are not equivalent and measurable prehybridization parameters can be predictive of hybridization performance as determined by replicate consistency. When hybridizing target derived from two cell lines to high and low quality replicate pairs (n = 50 pairs), a direct and significant relationship between prehybridization signal-to-background noise and post-hybridization reproducibility (R2 = 0.80, P < 0.001) was observed. We therefore conclude that slide selection based upon prehybridization quality scores will greatly benefit the ability to generate reliable gene expression data.
Carbocyanines↗
Resolution of clonal origins for endometriotic lesions using laser capture microdissection and the human androgen receptor (HUMARA) assay.
OBJECTIVE: To determine the clonal origins of endometriotic lesions using laser capture microdissection and PCR-based HUMARA assay. DESIGN: Molecular genetic study of human tissue. SETTING: Molecular genetics laboratory in an academic setting. PATIENT(S): Twenty patients with endometriosis. Forty specimens of endometriotic lesions from these patients and one specimen of normal endometrium were analyzed. INTERVENTION(S): Laser capture microdissection was used to harvest epithelial cells from single and multifocal endometrial lesions from paraffin-embedded and frozen tissues, and their clonality was determined with the HUMARA assay. MAIN OUTCOME MEASURE(S): Polymerase chain reaction-based HUMARA assay of clonality. RESULT(S): Thirty-eight specimens were polymorphic and thus informative. Most specimens were monoclonal, as determined by the HUMARA assay. In four specimens of multifocal lesions, polyclonality was detected, but upon more refined microdissections and further analyses, we found that each focus was monoclonal individually. CONCLUSION(S): Previously reported polyclonality is very likely to be attributed to the pooling of multifocal lesions or contamination of normal tissues. These results suggest that endometriotic lesions were monoclonal in origin, and in the case of multifocal lesions, each focus originates monoclonally; hence, different foci have independent origins. The monoclonality of endometriotic lesions suggests that they may carry neoplastic potentials, and the apparent independent origins of multifocal lesions suggest that reconstruction of individual lesion histories may help us to understand the initiation and progression of endometriosis.
Adult↗
The best-fit model for endometriosis.
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Endometriosis↗
Preferential transmission of type 1 diabetes from parents to offspring: fact or artifact?
It has been widely reported that men with type 1 diabetes (T1D) tend to be more likely to transmit the disease to their offspring than their female counterparts in Caucasoid populations. Several theories to explain this preferential transmission have been proposed, but so far none of them has been unequivocally proven. Whatever the mechanism, confirmation or refutation of this observation is nonetheless important and practical to the design of future genetic studies of T1D. We carried out some statistical modeling of the preferential transmission. The well-established fact that males have higher a prevalence of T1D than females, an apparent sex difference in fecundity, and a possible misclassification of gestational diabetes mellitus (GDM) as T1D in women have been considered. We demonstrated, first, that the ascertainment of study families through the affected offspring with T1D would generate a higher proportion of fathers than mothers having T1D, even though there was no preferential transmission at all. This can be explained by the male preponderance in T1D prevalence as compared with females, coupled with a greater likelihood of being selected and/or recruited for study in families with T1D fathers due to the fecundity difference. Second, when the study population is ascertained through affected parents, misclassification of mothers with GDM as T1D, and the existence of male/female difference in fecundity in conjunction with a birth order effect, can contribute to the observed preferential transmission, even though there was none. In light of the plausibility of assumptions employed in the analysis and, in particular, an apparent failure to critically examine the effects of these causes of bias in earlier studies, it is perhaps prudent to say that the jury for the existence of preferential transmission in T1D is still out.
Diabetes Mellitus, Type 1↗
Combined segregation and linkage analysis of HLA markers in familial psoriasis.
Marker-based segregation analysis (MBSA) is a modification of a published method of combined linkage and segregation analysis (Am J Hum Genet 51: 1111-1126, 1992), to determine whether a candidate gene known to be associated with the disease of interest is truly segregating with the disease in families. Here we outline the conceptual basis of MBSA and present a Monte Carlo method for significance testing. The method is applied to PSORS1, a locus within the major histocompatibility complex (MHC) for which linkage and linkage disequilibrium with psoriasis has already been demonstrated. The results are very consistent with our current knowledge of PSORS1, and suggest that MBSA can provide useful information on genotype-phenotype relationships such as penetrance and allelic heterogeneity.
Chromosome Mapping↗
Sibling recurrence risk ratio as a measure of genetic effect: caveat emptor!
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Bias↗
Conditions to ensure competitive hybridization in two-color microarray: a theoretical and experimental analysis.
We derived a theoretical model that explains certain biases observed in the two-color microarray hybridization experiments reported in the literature. We show that true competition is achieved only when the hybridization kinetics of the two differentially labeled probes are the same. If the hybridization kinetics of the two differentially labeled probes is different, which can occur when the labeling and hybridization conditions for the two probes are dissimilar, then differential expression observed becomes a function of the amount of the target (i.e., DNA spotted on the slide). We use this model to validate the microarray methodology by determining the differential expression of four select Arabidopsis genes and two human genes (beta-actin and GAPDH) as a function of the amount of target arrayed. We show through both modeling and experiments that the rate constants for Cy5- and Cy3-labeled probes are the same under our exrimental conditions. Therefore, the target concentrations need not greatly exceed the probe concentration. It is obvious from the data presented that a simple treatment of an individual hybridization rate calculation does notfully describe what is occuring in today's complex, multispecies experiments. The method of validation is easily implemented to ensure data reliability by two-color microarray.
Arabidopsis↗