A STUDY OF BARR BODIES IN CASES OF PRIMARY AMENORRHEA.

BACKGROUND: Barr body (or) X- chromatin is a heterochromatin mass seen in all somatic cells of females species. They account to nearly 80-90% in females and 1-3% of cells of normal males. Primary Amenorrhea a clinical condition is of varied aetiology, however Genetic factors being the major cause. Either a structural or a numerical anomaly like X- monosomy of a female results in failure of commencement of menstruation. Identication of chromatin negative condition in patients of primary amenorrhoea constitutes my study. The study i METHODOLOGY: s conducted on 58 patients who visited Obstetrics Gynaecology clinics Visakhapatnam district with presenting complaint of primary amenorrhea. Buccal smear examination is done to all the patients and observed under the microscope for Barr bodies. Photographs were taken and the observations were tabulated and analysed. Absence of Barr Body was ob RESULTS: served in 28 cases (chromatin negative) and 26 cases were chromatin positive and 4 cases showed mosaicism. Primary CONCLUSION: Amenorrhea due to chromosomal aberrations is a serious condition as it is associated with intense psychological trauma along with physical. In Turner's syndrome single X-chromosome is present (45XO), the subject is female in phenotype, but the ovaries are rudimentary (Streak Gonads) and absence of development of secondary sexual characters. So buccal smear is a simple, rapid test that will enable us to decide which patients are to be referred for further investigations to conrm the diagnosis.

COMPARATIVE STUDY OF EFFICACY OF PAPANICOLAOU AND ACETO-ORCEIN STAINS IN DEMONSTRATING BARR BODIES IN BUCCAL MUCOSAL SMEARS

Introduction: Establishing one’s sexual identity has a critical role in medical conditions like ambiguous genitalia and in crime investigations. There are various investigations to determine the sexual identity of a person and Barr body evaluation in buccal smears forms the first line of investigation. Barr body estimation in buccal mucosal scrapes has been demonstrated by using different stains like Papanicolaou, Aceto-Orcein(AO), Feulgen, Guard, Cresyl violet, Carbol fuchsin and fluorescent staining methods, but with varying efficacy. The current study is done to evaluate the efficacy of Papanicolaou and AO stains in demonstration of Barr bodies. Materials and Methods: A total of 207 medical students were included in the study. Two buccal smears were collected from each student and subsequently, one was stained with Aceto-Orcein by squash technique and the other with Papanicolaou stain. Both slides were evaluated for percentage of Barr bodies using 1000x magnification and cytomorphological features in 400x. Results: The percentage of Barr bodies in AO stained slides ranged from 5-18 among females and 0-8 in males, while with Papanicolaou stain the ranges recorded were 4 – 12 in females, 0 – 2 in males. The accuracy of AO and Papanicolaou stains for detecting sex accurately were 97% and 91% respectively. Evaluation of the buccal smears was better in AO stained smears because of the clean background and better cytoplasmic and nuclear contrast in comparison to PAP stain. Conclusion: Aceto-Orcein staining method is rapid, economical, accurate, reproducible and comparable to Papanicolaou staining, for the detection of Barr body in buccal mucosal smears. Keywords: Aceto-Orcein, Papanicolaou, Buccal smears, Barr body.

The B-side of Xist

Female mammals express the long noncoding X inactivation-specific transcript (Xist) RNA to initiate X chromosome inactivation (XCI) that eventually results in the formation of the Barr body. Xist encompasses half a dozen repeated sequence stretches containing motifs for RNA-binding proteins that recruit effector complexes with functions for silencing genes and establishing a repressive chromatin configuration. Functional characterization of these effector proteins unveils the cooperation of a number of pathways to repress genes on the inactive X chromosome. Mechanistic insights can be extended to other noncoding RNAs with similar structure and open avenues for the design of new therapies to switch off gene expression. Here we review recent advances in the understanding of Xist and on this basis try to synthesize a model for the initiation of XCI.

X-Chromosome Inactivation: A Crossroads Between Chromosome Architecture and Gene Regulation

In somatic nuclei of female therian mammals, the two X chromosomes display very different chromatin states: One X is typically euchromatic and transcriptionally active, and the other is mostly silent and forms a cytologically detectable heterochromatic structure termed the Barr body. These differences, which arise during female development as a result of X-chromosome inactivation (XCI), have been the focus of research for many decades. Initial approaches to define the structure of the inactive X chromosome (Xi) and its relationship to gene expression mainly involved microscopy-based approaches. More recently, with the advent of genomic techniques such as chromosome conformation capture, molecular details of the structure and expression of the Xi have been revealed. Here, we review our current knowledge of the 3D organization of the mammalian X-chromosome chromatin and discuss its relationship with gene activity in light of the initiation, spreading, and maintenance of XCI, as well as escape from gene silencing.